Hello again!
It appears that i was stupidly optimistic when I thought I could advance this for November.
Sadly, I couldn't, which means I had to hold everything in my head
Even now, my eyes ache, staring at the computer 
So, this'll be quite rough, don't be surprised.
So, I was going to tackle Enchantment, which means Verditius
.
In hermetic Magic, you're best at enchanting in your best TeFo combo - Yet, verditius is only known as a "great enchanter", not even for his expertise in Terram - Something which the rules don't support. I LOVE what Guy Leopold did in Sub Rosa #22 (and it is coherent with what I write here, as well as filling a "gap" in history, from Pagan priests to Magicians), so I'll at worst propose an alternative version, for those who prefer a Magical Verditius, at least focusing on what existed besides, and made him, great. But it should be able to coexist.
How did it work, before the Order?
I figure Mercurians did what Mercurians do, that is, cast Rituals. When you're a magician who doesn't know how to do it, how do you create a magical item? You "store" a spell for later use. That's it. You use Waiting Spells. I figure that, after a while, there was a Breakthrough, and someone found a way to create more permanent, stable containers; in short: Invested items.
How could that have worked, in our Domains model?
I imagine there was Something akin to an " Enchantment" domain, used to handle vis, and open items in the lab, for up to twice the Domain pawns / season.This was, obviously, integrated in MT
But, once opened, how do you invest?
Let's say your Domain must be superior to the spell's Magnitude, and it worked like Hermetic enchantment, pitting twice your Domain + Int + Aura (so MT was a BIG improvement for everyone) vs the spell level.
Yup, those Mercurians sucked at enchanting
^^ But how did they do it? With Effect expiry. Let's say it gives a bonus equal to the multiplier, so an enchantment which lasts only 1 year gives +10 to your lab total.
Charged items could also have been developed, especially by witches
(potions) and magicians ( scrolls) 
Enter Sandman. I mean, Verditius
^^ By adding his Craft score, he could make items that lasted longer, or make them faster.
Unless... What if he was something else?
In older RPGs, a magical item is, typically, something which gives a bonus to its use, like a +2 sword, or a + 3 chainmail. Yeah, you got it. Excellent quality items (C& G p 69), which, as they ignore MR, would have seemed miraculous to Bonisagus and his peers. All without vis! Let's assume he was ( obviously) Touched by the Magic Realm ( c&Gp71):A high Craft score would also have let him do Wondrous items ( C&G p70), which are surprisingly easy to create, especially if, as Guy posited, you've got an applicable Faerie Sympathy, and, also, require no vis to create.
Wondrous items are normally limited to 2 forms, but Verditius could probably create any enchantment within his Domains, adding the appropriate score, if any

Magical indeed^^. I'd also add that Verditius was smart enough to work in, literally, a forge fit for a god
, so, presumably, with a very high Innovation, and maybe Raw Materials, ratings. And who's to say he didn't have an Anvil of Quality, or something like that? While I'm at it, I also Wonder: Wouldn't Tools of Quality add to a (magical) smith's Craft total?
If you add an applicable Domain, Verditius suddenly becomes a crazily powerful item crafter.
To me, verditius being a great enchanter also points toward using less vis to create an item ( as per Verditius Magic, "the number of pawns of vis needed to open the enchantment is reduced by the magusās Craft score, to a minimum of one pawn"), which jibes well with Touched by (realm).
He could thus be behind Lesser Enchanted devices, which would be an improvement for both our poor Mercurian Magi
, and the non-mercurian ones

Note that Wondrous items are a link to the person they're crafted for, which could hint at Talismans, lacking the "excess vis limits" vibe, for which I had another idea, inspired by Vincent Garcia-Gomez's piece in Sub Rosa #16: What if one of the primitive ways to create sentient Magic items was just to "saturate" Something with vis, and then, experiment, trying to cram more, until something happened? In that optic, the increased vis capacity of Talismans would be a serendipitous Discovery.
I realize that, since I'm only using 1 hand, this is taking me longer than usual, esp. that I have to "store" everything in my head.Result: I'm lost, I don't know where I was or what I was doing
.
But what about the Rings, you'll ask?
As I said, we have no idea of what kind of Magic was practiced by Verditius. Save for his Runes, taught to him by Wayland Smith (Hoh: TL p 127).
IMHO, Tolkien had it right: the effects must be subtle, that's why everyone remembers the mafgic of Flambeau
and Guernicus
, whereas
is shrouded in Mystery.
So, I'd say he had 1 ring per rune, for each of Health, Sight, Pain, Ice and Man. Maybe replace Ice with Harvest, or Loyalty? Too tired to work on this more, I had to postpone it 
Going back to Guy Leopold's article, I've noticed that that you can almost keep it as it is, and just shift the focus from Faerie to Infernal
. After all, Where did Verditius great skill come from, of not being Mentored by Demons
, which explicitly allows you to "exceed the maximum skill level for a given age provided by the character creation rules".
This also fit well with House Verditius being, one could argue, the most sinful house: We begin with Hubris being the Sin of Pride, the " covet device" trait from Item Attunement being Greed, and the Vendettas being another sinful trait, like Revengeful? Each Ring would then be linked to a different sin. I'd add Murder (also present in the story of Verditius) and Blasphemy ( The whole " Cult of Verditius" thing, see HoH: MC p109)
.
So, I'll stop here for now. I really should consult my books for inspiration, but my time and energy are limited, as well as my " head storage" capacity.
Have fun! And long live Ars Magica 