Ok, I'll stick with the original write-up you came up with for me. You know, to keep things simple to start with. I'll add that to my character thread at some point.
I do, however, need help with the lab and familiar portion of this. If everyone has one, I should at least be involved in defining the ones that impact my character, no?
Just as an FYI, I'm planning for Pere to have a townhouse in Palma with his sanctum in a regio on-site. I'm also planning to buy Secondary Income as many times as I can manage. 
Familiars are mostly unchanged from the core rules. See p. 103-106. Designing the familiar itself is usually done using the rules for magical creatures in Realms of Power: Magic. Since I'm guessing you don't have that book, I can help you design a familiar if you're planning to have one. PM me if you're interested.
All the rules for lab improvement are in Covenants, so that may be tougher to walk you through. In brief, for every level of Magic Theory you have above 3, you can add one point of virtues. Virtues normally add bonuses to lab scores for a specific Art, specific activities (i.e. inventing spells), possibly to all lab scores. Bonuses are usually +1, occasionally +2, and it usually takes a major virtue to get a +3. You can also take lab flaws to reduce or eliminate the cost of virtues, which apply penalties that are roughly equivalent to the bonuses given by virtues. And to make everything more complex, there are free virtues (and flaws) that you can take regardless of your MT score.
One thing I'm fuzzy on is how long it takes you to add virtues to your lab. I always thought you could only add one virtue per season, but after seeing some of the Andorra characters trick out their lab completely in a single season, I'm guessing I was wrong.
Well, I have MT 2, so no virtues there. I'll have to scan the stuff in Covenants to see about what I can do.
And don't worry about books - I have a family member who has a hobby shop, not to mention friends IRL that I can borrow books from.
Sent from my iPhone using Tapatalk - now Free
I decided the core rules suck 
You refine your Lab, that is a separate whole seasonal activity.
The House Rule is that it shall take you only a single season, one single season, to install a balanced number of Virtues & Flaws (in accordance with extra tolerance ascribed for Refinement and Size).
Otherwise, according to RAW, it takes one season to install a Minor Virtue and two to add a Major Virtue. And I looked at the math, and realized that this didn't save you any time or effort at all. Maybe when you are old and all your Arts are over 20, then this might save you some time. Otherwise it is pointless.
It's a bit worse than no virtues...
You may want to swap your Order of Hermes Lore, or one of your other Abilities with a score of 3, and MT scores around. 3 is considered a minimum for MT, and anything less than that can make things difficult. Granted, those other abilities might be considered important, but I think your Mater would consider Magic Theory 3 an imperative, just from the point of view that she isn't creating a deficient Merceris magus.
Yea, Magic Theory 3 is sort of expected of a newly gauntleted magus 
(ArM5, page 32, first column, last paragraph, in the middle
Now if only I'd known this before Vocis burned all those qp on lab virtues... 
aaaarrrrgggghhhh
Did you not notice the time I rewrote those rules to account for the fact that you spent less than half the qp you should have? You just bought Virtues for an unrefined lab, and didn't include Flaws or increase the Size. So I had to alter the cost structure so that you could have afforded a larger lab and invented a rule to pre-refine the lab, adjusting prices so that you could get exactly what you have for the price you paid.
And hold on a minute!
That's when I wrote the easy refinement rule. If you were aware of one, then you should well have known about the other.
And I will offer a refund.
I do have a revised economics system I keep taunting about, and everyone would get a refund. The changes are simple...
And changed it up. Dropped Philosophiae to 2 and increased Magic Theory to 3.
I don't think the Aura alignment should affect Acclimation or Bound to Magic. I just wanted the bonus to lab and spellcasting. Rego would work just as well for me, but is harder to explain in an underwater cavern. Is it possible to take Favorable Aura as explicitly only affecting Hermetic activities? If so, I'd add
+1 Favorable Aura: Aquam alignment
-1 Unhealthy Feature (There is nothing particularly healthy about living underwater.)
+1 Aura Strength for a total Aura of 4
+2 Aura Size large enough to cover the whole cove
+1 Difficult Access: Sanctum is an underwater cave inside the cove.
+1 Hostile Environment: This is an underwater sanctum for a maga who is part fish and does not need to breathe.
+1 Special Feature: A naturally occurring whirlpool is within the sanctum, but it is completely contained and does not cause any currents outside the cave.
+1 Private Income: Thalassa scavenges sunken ships for their treasure, bringing in an average of £15 a year.
-1 Flickering Aura Thalassa must sink at least one ship somewhere between Mallorca and Sa Dragonera every summer, as a sacrifice to Poseidon; elsewise, the aura in her cove will diminish.
Your Might is 2? According to the Acclimation chart, you need to spend at least half your time in an Aura level of 6, or all of your time in an Aura of 1. I also think the scale is screwy and want to rewrite it. But let us leave that aside.
You still have an imbalance of Aura related Boons & Hooks. Those must balance. You only need an Aura of 3 attuned to Aquam (as I do think it applies towards Acclimation for creatures with an Aquam might score). But even at 8, that still keeps you in the "Half-Time within" zone, so I am not worried about the score. I am trying to discourage one single site being sufficient for a whole covenant, or even the entire chapter. But this is an underwater cove, which works for me 
So I recommend...
Thalassa's Quarter
+0 Journeywoman: Make note of this
+1 Aura Strength for a total Aura of 4
+2 Aura Size large enough to cover the whole cove
+1 Favorable Aura: Aquam alignment
-1 Flickering Aura Thalassa must sink at least one ship somewhere between Mallorca and Sa Dragonera every summer, as a sacrifice to Poseidon; elsewise, the aura in her cove will diminish.
(This should be symbolic; the ship can be scrap and empty, or dunked and raised back up again. eh?)
now two more to balance aura boons...
-1 Monster: There is something swimming out there, not sure what. Thalassa has not yet had to face it and hopes not to any time soon.
-1 Uncontrolled Regio: Near Thalassa's cave there is a "lost" islet between Mallorca and Sa Dragonera, that can only be seen certain times of the year (autumn and spring) in certain weather conditions (foggy mornings or gloomy twilights just before a storm).
+0 Island
+1 Difficult Access: Sanctum is an underwater cave inside the cove.
+1 Hostile Environment: This is an underwater sanctum for a maga who is part fish and does not need to breathe.
-1 Unhealthy Feature (There is nothing particularly healthy about living underwater.)
+0 Rough Construction: I am going to add this one to the list, since it aptly applies to your set up.
+1 Special Feature: A naturally occurring whirlpool is within the sanctum, but it is completely contained and does not cause any currents outside the cave.
+1 Private Income: Thalassa scavenges sunken ships for their treasure, bringing in an average of £15 a year.
then add...
+2 Hidden Resource (x2): I took it out of the main list to give everyone room for a minimum aura. If you would do me the favor of holding on to this for the rest of us, then the two extra hooks I asked for (Monster & Uncontrolled Regio). You are the sg here, I am the Producer and you are the Director. Keep these two on the back burner until you need a wildcard hook to throw at a player to chew on ("here Roberto, go hunt the sea serpent while Pere and Guillaume go investigate the ghost island")
I know I should have known. I wasn't asking for a change or refund. I was combining kicking myself and warning Scarecrow against buying virtues with qp into one all-encompassing statement. Calm down, have some dip.
I am thinking of one more revision, but it will have to wait until Sunday. I don't think balancing Aura boons & hooks is working, and I think 6 points is too many if you start with Aura 3. Maybe start from 0, or from 3 with 3 points. Instead of a balance, free that and just set a cap into place. The idea is that there isn't any one single location with an aura both large and strong enough, and easily accessible, for an entire chapterhouse or covenant. There are strong tiny ones, or large weak ones, or moderate ones located underwater, etcetera.
That Resources boon is too high. Fo silver or a book or a vis source, it sounds right. But a queen of vis is a bit much. Covenant built boints are whack. I will reset that to our QP scale.
And I promise to roll out my Hermetic Economics system soon. Just for you guys to view and judge. I shall not implement anything that the troupe does not agree to.
Now, for me to meet all these promises, you will have to wait until Sunday, maybe Monday. :mrgreen:
RAW, yes, but questionnable, and against the spirit of the rules. If you go like this, Vort also based most of his concept upon the RAW.
For exemple, the "No Fatigue" virtue clearly says that, because of the restrictions on magical beings improvement, they probably won't do much with the 2 extra seasons per year. Thalassa had no such problem, having a MM of 0, which made that major virtue even more powerful.
This is awesome. I love what you're doing here, there's really, really, a good idea, probably enough for a SR article. This would need to be simplified, but I think there’s really something here.
I love you. And the sharksignal.
You know what?
Tell me what you want, in as much details as you do, and what powers you want it to have. I’ll create it for you.
What I did when revising Aranka (the mercurian summoner) is use the vis by cycle to buy BP for the spells I wanted her to have learned from a text, instead of trying to judge if some spell could, or not, be reasonably acquired (Usually, I go by “Nothing the first cycle, then corebook ok, outside not”). I think it worked nicely, and provide a good ingame mechanism for that.
Good idea. I’d just put twice the cycles.
Another thing I’d do is take inspiration from the mangas: Age is experience and power, youth is energy and potential. We already have age worked out, but for youth, I’d have 2 things:
So, for exemple, vibria, our young PG maga, would have had Confidence 2 (18), gained 20 extra xp per year the first 5 years of the covenant, and 10 for the 5 years afterwards. This keeps the difference of power between older and younger magi, yet shows the blossoming of the youth.
Nice. It screams “Pyaray” to me, but nice.
I don't know if there's anything about this in the rules, but it sure makes sense.
Thx. When will you propose? :mrgreen:
I hope Ryu find these interesting for his lab. I am a fan of underwater caves myself. Presteris of flambeau (one of our magus in the Manx saga, a salt water elementalist) had one of these, with anchor and shaft of light included. the anchor belonged to a rival and he dragged it from Edinburgh to Mann (all the way around Scotland) just because of that, since he wanted a souvenir of the wizard war. It was a really cool lab, even if somewhat humid.
Xavi
Fixer: I appreciate the offer. However, I don't know what can be done , so I don't know what I may or may not want.
I also really want to learn how to do it myself at some point, so I just need some guidance on how to do it.
Sent from my iPhone using Tapatalk - now Free
Once i find a good enough ring, of course! 
Then, first step, think about it. What kind of animal would you think appropriate? What would you like? What would you want it to do, how do you want it to be? Try to picture it with your character, how could they cooperate?
The rest is easy.
You've got a basic might (IIRC, 10 for a normal saga, 15 for a high-powered one like in Andorra. Mallorca might go for 10). Adjust for size as in the corebook.
Select the characteristics as seems appropriate. Adjust for size (+/- 2 Str and -/+1 Qik by size point above or under 0).
Add mundane animal qualities and all from the bjornaer chapter IN HoH: MC, that are appropriate for this kind of animal
From RoP: M, select magical qualities and flaws. He has a number of "free" points equal to its basic magic might. This is where you select the type of power he'll have (lesser, greater, focus, ritual)... We can help with that.
Is it a young animal (spring), an ancient creature that as seens empires fall (winter), or something in-between? This gives you a pool of XP to spend on appropriate skills.
Design the powers based on the above. We can help, it's easy.
Ryu, are you familiar with the Emerald Grotto off the Amalfi coast? I know it's not the same place, but it's certainly a beautiful inspiration for Thalassa's sanctum. There's a Blue Grotto nearby which has a waterline entrance, while the entrance to the Emerald Grotto is entirely submerged, if I recall correctly.