I have noticed what I consider to be a major hole in the texts, which is that while a lot of discussion is given as to how magic can affect mundane crafts and artwork, very little consideration is given to doing things the other way around. What is the effect of having truly excellently crafted glass wear in your lab? If the statue that is a major focus in your lab was made by an accomplished maestro instead of a second year apprentice should that not have some effect to the resonance or bonuses it gives? At minimum a difference to the aesthetic bonus?
Books are allowed a small bonus for a competent scribe, illustrator, or bookbinder, but if you get extraordinary craftsmen who would make the book as unto the original Book of Kells in terms of presentation and artwork people get bent out of shape if you suggest that should get an additional quality bonus... but somehow using a dragon hide to bind the book should allow for a bonus that master craftsmanship will not...
My position is that additional boni from skilled craftsmen (above the +1 for each of scribe, illuminator and binder) are not supported by RAW. The workshop total is totally irrelevant there. The book would certainly look more impressive, but that would not translate into a higher Source Quality for reading the book.
Otherwise, we get into absurd situation where the contribution of the physical quality of the book could potentially overwhelm the quality of the writer. That also leads to books with higher and higher Source Quality in books, which means faster and faster advancement.
As for using dragon hide and such, this is already taken into account through resonant materials (Covenant p.87), which can grant up to 2 additional points of quality (1 for purchased materials, 1 for materials obtained in stories).
Yes, I know that the dragon hide is taken into account, my point is that given that magic is supposed to be about things reaching their ideal state he idea that better craftsmanship is less significant than a dragonhide's resonance seems fundamentally wrong to me.
As to the workshop total exceeding a mage's ability in determining SQ, even for a tractus a SQ can get up to 14, which for a workshop bonus to equal that would require a workshop total of 51, where the typical workshop total for the standard +1 bonus is 6. And this is before any rule which could be included to divide such a bonus or cap it at something other than +1.
This also doesn't address the main point I was making here, as opposed to rehashing what has already been discussed, which is that if I place a statue in my lab as a minor or major focus, the quality of the craftsmanship is again considered irrelevant, where the artist has now (through Artes and Acadamie) generated an aesthetic total which I think should be in some way referenced.
Ultimately the issue here is that these points have simply not been addressed at all, despite a number of supplements which realistically should have addressed them I can use a craft+dex on an "opened" faerie and with a total of 24 can give that faerie a new major virtue or flaw (spending their pretenses) but have exactly the same effect on the resonance and aesthetic quality of a lab making a statue as a 1st year apprentice.
I know that this is something that I've argued with you about, but since that was on a saga board instead of a general board (which most people here won't have read), I feel it's necessary for me to make my points again here.
One of the reasons why the physical quality of a book (or of a lab, for that matter) only matter a little beyond the basic "competent" (skill 8, for a book) or "superior" (for a lab) is because the supernatural properties matter much more than the mundane. It doesn't matter if the statue in a magus' lab is a masterpiece or a roughly hewn stone shape, because it is the "idea" of the statue that provides a supernatural bonus to lab activites, nothing so simple as its physical properties. In much the same way that the magnificent cover of a book has very little to contribute to the quality of the information contained in it.
That's how I read this in the various sourcebooks. Of course, I don't have Art & Academe so I have not read it, but I believe that this is the spirit of the rules as presented in Covenants for both books and labs, and there is nothing in City & Guild that contradicts this. All IMHO.
Now, there is nothing preventing a SG or a troupe from implementing house rules that provide for larger boni. But that would be on a saga-by-saga basis, and that would have impacts on the power level of those sagas.
Which is something we disagree with, but my greater frustration is simply that there is no RAW to this- the entire concept is entirely neglected, even to say "these thing do not effect magical totals, including books and lab" would be better than what there is now. The only thing it does say is in C&G where the quality bonus for a high quality item is added as a bonus for enchanting it.
Which to me undermines the idea that it is the idea of a thing rather than the quality of it which matters magically, which suggests that quality should matter in terms of magic.
At bare minimum the aesthetics score should have some impact on the aesthetics of the lab it is placed in. Again, nothing.
One of your very own examples is given right in Covenants! 
Page 116 has three free Virtues that increase your lab's general quality and safety in exchange for increasing upkeep, because they represent having finer ingredients, better equipment, and better tools, with the equipment example in fact being fine Venetian glassware. (Whether or not you consider Venetian glass any finer than other glass is completely irrelevant here, it's the thought that counts.)
Another thing you're missing, and something that I find I disagree with Arthur's stance on, is the idea of putting better versions of things into your Lab. The SG can make judgment calls for exceptional circumstances, but for the most part, there isn't a whole lot better than what magi already use for these things. According to page 70 of City & Guild and 106-107 of Covenants, unless they have flaws saying otherwise, magi already demand that everything in their labs (especially the things they're actually working on, like enchanted items) be close to perfect in quality, else the ever-perfection-seeking properties of magic will indeed be muddled. In other words, there aren't better versions of these things because the best is generally already being utilized; otherwise, it wouldn't be providing its bonus in the first place.
Hope that helps.
Aside- understand the stance that magic seeks to make everything more perfect, but always thought that it was more about it being better for its purpose. I find the term perfect a little ambiguous; ie. perfect for what?
Shouldn't intent play a part, or is the items constructed form always applied?
A Perdo lab might have a fine and once grand feature, which is damaged and decaying. With use for Perdo magic, won't the Perdo seek to further the methods of decay rather than restore the item?
But where an item has a workshop score or aesthetic quality, shouldn't these numbers mean something beyond "venetian glass" what is the workshop score equivalent for Venetian glass? I would guess a 12 which generally gives a +1 benefit. So if we have an exceptional glassblower with a workshop score of 18 do all the +1 bonuses get tripled for +3? Would the difference in cost be offset by it being a covenant or PC who can make such fine wares, or does it also triple the upkeep modifier?
I was nice enough to point out the free Virtues related to the quality of labstuffs, and you didn't even read them? 
Seriously, they're on page 116.
I'm of the opinion that labstuffs are already at a +1 bonus because it's the only way I can imagine them not providing lab penalties due to constant breakage and lack of Sympathy, not to mention the statement on Quality in the lab section of Covenants. This would be increased by the Free Virtues, Superior Equipment and Superior Tools, which each raise General Quality and Safety by one (having them both, then, is twice the benefit). The main argument against this is that Superior (Thing) can have its Upkeep change minimized by craftsmen with Craft scores of 6, but I have no idea what kind of workshop total results from a joint effort by Craft 6 crafters without knowing the other variables.
However, in the end, the specific quality doesn't really matter. In your sagas, the average lab could use barely-functional equipment, with quality-reducing Flaws (like Decaying or Inferior Equipment) knocking it down to "I suppose this thin branch of wood could be hollowed out into an alembic" level of crap quality, and while I personally think that runs a bit contradictory to the fluff, it wouldn't itself break any rules. The rules from C&G for quality are independent from the Covenant rules for lab quality because they run on two completely different scales of "quality."
The Virtues I mention specifically increase General Quality (effectively, your entire Lab Total) by one, along with Safety. That's it. Your sagas could run like mine, where your glass in already pretty nice, and then you install Superior Equipment into your Lab and it now has beautiful, ornate, and extremely precise Venetian glassware, making the lab safer and more productive. Or, in the aforementioned "everything is crap" saga, it means you finally have something people would consider worthy of calling a glass beaker, whereas before you mostly had chunks of broken glass melted back together in deformed cups. It doesn't change the fundamental effect.
What those Virtues basically say is "your lab's stuff gets better enough that your lab reaches a new level of safety and productivity." That's really all there is to it; the rules are saying "do what you want with the craft quality of your equipment or whatever, but your lab has been made as safe and productive as it can be through an increase in equipment/tool quality, so if you want more, you'll need to apply yourself in a different area of lab improvement." This even applies to Aesthetics; none but the most discerning and simultaneously most vain visitors will actually care if your glass is shinier and more ornate than your neighbor's already impressive shiny and ornate glass. It gets to the point where a little stops going a long way.
Too long, didn't read? Basically, the C&G quality rules aren't intrinsically tied into the Covenants quality rules, so an increase in C&G quality doesn't necessarily have any meaningful effect on Covenant quality. It can have a meaningful effect, certainly, but it also doesn't in all or even most cases.
... And just in case you still don't want to read those Virtues, they each increase Upkeep by one, so how much they cost depends entirely on how much maintaining your laboratory already costs. Logic!
I have read it, multiple times, I think you are also reading a lot into it.
This is in part the problem. It never actually states the indepedance of these rules, or that very high quality crafts do or do not give a bonus.
Even aside from this, however, is the issue of aesthetic quality. If I have a focus in my lab which gives an aesthetic bonus of +1 in the lab with an aesthetic quality of 6, shouldn't an equivalent item with aesthetic quality of 15 give a higher bonus? We are talking aesthetics here, not magical properties, which only helps to build reputation, though give the whole concept that higher quality=more magical I wouldn't want to rule out magical bonuses either. There should be rules for this in A&A, but there is nothing.
Honestly it goes back to my original headache which is that it is hard to find 2 books in the system where one isn't the core book where you won't find some kind of conflict if you look hard at it.
The other thing is this- if it is "completely separate" why publish it as part of the same system? It seems to me that "completely separate" is just a euphemism for "we don't consider it part of the real rules"
I didn't mean completely separate as in the rulesets themselves don't work in the same game. It's just that a +1 bonus on a mundane task doesn't necessarily translate to a +1 on magical tasks, because the two processes are related but not the same thing.
The Superior ____ Virtues, as I said before, basically mean "you've got stuff crafted with a high enough Workshop total that it makes it magically more significant and safer to use. Making it better wouldn't make it meaningfully more effective or safer."
As for Aesthetics... Again, unless the viewer is very discerning and equally vain, they won't care if your, say, sapphire-encrusted statue is higher quality and chiseled more precisely than the same item somewhere else, because they both look great, and those further improvements don't matter enough to the general population to have a noticeable impact on your reputation for good aesthetic sense.
It's clear we fundamentally disagree on whether or not there's even a problem with this whole process, though. As such, I don't know if there's a point to continuing to debate. Hopefully somebody else can provide a better explanation than me.
Except that 1) it never states that it does not provide a bonus to magical tasks and 2) it does state that it provides a quality bonus to enchantment. I really don't see anywhere that there is a reason to presume that it does not add to magical tasks.
As for aesthetics, if people don't care then why does the statistic even exist in either context- that of labs or the aesthetics of the artwork? The argument makes no sense, and really seems more like a hand waving "don't look behind the curtain" kind of answer. Both the lab and the artwork have aesthetic stats, and you are saying that there is no relationship between the two because nobody cares about aesthetics?
I don't think he meant "aesthetics don't matter," I'm pretty sure he meant "once something is already extremely nice and extremely fancy, making it more nice and more fancy isn't something most people would even notice." That's how I read H&G's argument on aesthetics, anyway.
Ah, but you are right! It does not say anywhere that the mundane quality bonuses don't apply to magical activities! (I'm actually being sarcastic, because a Lab Total isn't even an activity that uses the implemented tool as a channel for a skill... A Lab Total is a LOT more than a mere Magic Theory check.) This means that every individual beaker, alembic, measuring tool, or, hell, ANY form of tool/equipment will be giving individual +1 bonuses to my Lab Total! Buying (relatively cheap, by covenant standards) better equipment will increase my Lab Total by +100s! Muahahahahahaaa! 
Sarcasm aside, there are multiple points here, and this isn't a matter of "bwa ha ha I can get away with more power", the point here is primarily aggravated by lazy authors. If I have an aesthetics 6 statue in my lab which contributes +3 to the aesthetics of my lab because it is a major feature and my soldales has an aesthetic 15 statue that contributes 2 to his lab aesthetics because it is a major feature and more prominently displayed, how does that make sense? Whether it is a matter of minimum scores, or multiplying the aesthetic bonus by 1/5 the aesthetic score, I simply feel that something should have been said on this point.
Also I note that there are several of the free virtues, which are broken down into equipment, tools, and supplies, and support ca only be provided by 1/5 per craft, so it feels to me like a craft should be able to have some impact on a lab for being truly exceptional- for example if a craftsman with a quality +3 for glass blowing is supplying the superior equipment instead of it being venetial glass (and I mean all the glasswear, not one piece) then there should be some impact to that, even if it is reduced from the +3. The authors seem to have given no consideration to this.
A couple of possible limitations I could see as being more reasonable than "It just doesn't work" would be
a) bonuses are limited to the artist/craftsman's magic lore+1
b) the entire lab has to be financially supported by craftsmen (5 appropriate crafts), with the lowest bonus prevailing (note that non-PCs cannot get a bonus above +2, since they are limited to ability:6, and to get +2 would require a workshop bonus of +3 innovation, +3 materials, and an additional 6 points in assistants)
as to aesthetics, perhaps treat the aesthetics score as an experience score for lab contribution aeasthetics, so at an aesthetic score of 15 it would give +2, and an aesthetics score of 30 would give +3 to aesthetics (use 3x aesthetics for a major focus). Not that with the rules in A&A any artist producing aesthetic quality over 30 is not long for this world as they will be ascended (or descended in the case of infernal) to whichever realm is most appreciative of their artwork.
See, it all works out well and good if those rules apply only to a Focus. But the way you seem to be reading it still implies that every +1 higher my individual beakers/alembics get will increase my score. Which means that the logical conclusion to a full-lab upgrade would have a bonus of hundreds to the Lab Total... Or maybe just my Aesthetics score, in which case I still win.
I would generally justify it in two ways, personally. As far as aesthetics, C&G's aesthetics sensibly contribute to a Local Reputation... You know, the different Reputation types in the core book. Thus justifying why, in the rules anyway, there isn't an effect for nicer stuff. Because that kind of thing builds Local reputations, for making it at that, not Hermetic reputations for owning it. Magi are very practical people for the most part; owning something would only increase your Hermetic reputation based on its usefulness/health effects/sympathy. In other words, the Aesthetics bonus is "your Lab is more impressive for having a Focus," rather than "that Focus by itself is impressive." Because, I mean, that Aesthetics bonus is getting added to a whole for the room, remember.
As for the quality bonuses... I really don't understand the confusion. Better stuff is resistant to breakage according to C&G, right? Therefore, the increase in Safety. The increase in General Quality just has to do with Sympathy involved in better items being used. It has nothing to do with tools being able to affect mundane tasks but not magical ones, because that simply isn't true. Mundane bonuses to affect the magical... Skill checks. Which is where the problem lies. Items crafted with better quality provide bonuses to skill rolls, like Pre + Charm + Stress rolls. That's literally their function in the rules. It doesn't make sense to assume that they provide bonuses to anything other than skill rolls, because that's what they do, and that's what they should do anyway, because how else might they provide a bonus if their craftsmanship isn't making them do better at their intended function? Yeah, they provide bonuses to skill rolls... Of which Lab Total is not one.
Does that make sense? According to C&G, quality boosts an item's bearer's effectiveness when performing a skill roll associated with the item. Lab Totals are not skill rolls, so quality boosts provide no bonus.
That's an interesting analysis, aside from the fact that it completely misreads the rules in both Arts and Acadamae and City and Guild. City and guild states that the items give a bonus when used, it says nothing about a skill roll. Also the rules about aesthetics are in Arts and Acadamie, not City and guild. Finally you begin your analysis by assuming I am saying something I am not saying and being outraged about what I didn't say.
Also A&A's reputation does not specify that it is a local reputation, it says the reputation is depenant on the craft involved, and that reputation if for the artist, not the patron, it only indicates that a patron can get a reputation as a sponsor, and certainly nothing about the aesthetic difference for having high quality instead of low quality art as the focus of your lab. You assume there is no difference to preserve the ruiles as written in Covenants, but it simply makes no sense and you wind up throwing away good rules in order to maintain the book. As long as we are doing that why don't we throw away all this nonsense about the Aegeis needing penetration which is in later books but not the core rules as well?
The Aegis is a spell, who in the world assumed it would be exempt from needing to Penetrate unlike every other spell? 
Alas, I'm afraid I need to concede this argument on Aesthetics. You own a book I don't, so there's only so far I can work.
I appear to have failed at C&G, too. Silly me. I'll remember to enforce +100s to Lab Totals in any strict RAW games I play from now on. Gosh, I love rule failures. I suppose the only argument I have now is that you should lighten up about it, because the designers aren't perfect. But that's not my place to give you advice, so hulk out if that pleases you.
Well, often times it's the first line[sup]1[/sup] in the spell text description for Aegis of the Hearth. I'm not saying I agree with it as a good or even justifiable argument (I don't), but I've seen it often brought up as the only justification that the Aegis doesn't need to penetrate. Faith and Flame did at least explicitly state penetration requirements for the Aegis in the book, so maybe that's put to bed.
I'm picking out this answer on a phone, so I'll be brief. The reason having exceptional crafters doesn't make books markedly better is that Covenants is very early in the the line and I wanted, and was allowed to take a strong stand against supplement power inflation, which was an omnipresent problem in other popular game supplements at the time. Books are the main source of XP in the system, but it's also true for labwork, that if you allow magic to use money, which is trivial to acquire, to make XP easier to get, the system rapidly breaks. If you want crafters to substantially impact on qualities, then you need to lower the base scores for those who do not have them, not up the final scores for those who do. So, now, as a "lazy author" who spent yesterday travelling to a con to run an Ars demo, I'm going to leave the thread because it is making me grumpy. As a final thought: this group can't fix saga-internal disagreements like this because no-one's saga is or should be strictly by book.