So because my current saga is set on Malta, the Roman Tribunal is the nearest; this is giving me a chance to slowly explore the Roman Tribunal a bit at a time. Here’s my take on it:
The Tribunal is vis-poor. So how do they get their vis? Well, the domus magna of Mercere, Verditius, and Guernicus are all located here, and all those houses generate huge sums of wealth, measured in vis—Guernicus from the legal services it provides, Verditius in the form of vis paid to individual magi for their enchanted items, and Mercere makes vis by serving as a vis exchange. So it seems to me that the Roman Tribunal is a service economy; in contrast to Normandy, which solves its vis shortage by organized fighting, the Roman Tribunal provides services for magi throughout the Order. This also fits with the tribunal’s history of selling lesser enchanted items to mundanes.
If you’re a magus or a covenant looking to buy or commission an enchanted item, have a book copied, or a spell invented—if you’re looking to buy a familiar or even an apprentice—or even if you’re looking to do something naughty like assassinate someone, break into a sanctum, or scry, there’s probably a magus in the Roman Tribunal willing to do what you need, for a fee. Similarly, it’s not unusual for wealthy aristocrats in Italy to have a lesser enchanted or charged item, because magi regularly sell to all buyers, including creating demand for their wares by selling to both sides of a conflict.
In other notes, I reconciled the small number of covenants by assuming a fair number of additional unofficial covenants which haven’t been recognized as official because, to be recognized, a covenant must pass a unanimous vote of all other Roman covenants. This hasn’t happened in centuries. House Tremere is trying to reform this rule to make it easier for new covenants to form, with no luck.
I also use Timothy Ferguson’s in-progress work on Venice, with its leprous dogaressa, a Diana cult among the Venetian noblewomen, and a Faerie that thinks it’s Tytalus accelerating progress in Venice to bring the Renaissance early, in order for faeries to get new and more interesting stories.
I’ve thrown out most or all of the Infernal stuff, not necessarily because “there’s too many demons,” but because the demon stories are incompatible with both history and the Order in 5th edition.