These are the house rules for this saga:
It takes a spell of the 7th Magnitude or higher to cause Warping. The seventh magnitude is also considered an important milestone amongst magi. Archmagi will not consider a challenge from a magus seriously unless they have invented at least one original spell or enchantment of the 7th magnitude or higher. Newly gauntleted magi may not start with spells of the 7th magnitude or above.
Where the Virtue can cover a number of variations (Craft, Profession, Area Lore, etc.), Puissant will give a bonus to all uses of the Ability in question.
Getting ACs FIxed
There are magi out there who will spend a season fixing an AC for 4 vis each (1 vis for the fixing, 3 vis for their time). So anyone can get an AC fixed for 4 vis. It's assumed that you know relatively trustworthy people who can do it.