Organizing a tournament for a game that takes a long time is fundamentally challenging. You can't play 2 out of 3 games, you can't efficiently do round-robin, and any kind of Swiss format will be drawn from an unrealistic statistics pool.
Ultimately, I feel like Mage Wars is probably going to have to go the route of other "long" games in that, as far as tournament play goes, it's not going to be accessible to the 9-5 crowd on a weekday. I think this is going to, by necessity, be a game that requires the better part of a day on the weekend.
Saturday or Sunday tournament from 10:00 A.M. to 7:00 P.M. with a 1 hour lunch break gives an 8-hour window in which to run your event. At that point you could realistically do a Swiss format. The pool for statistic pull would be small, but should be accessible.
The weekday 9-5 crowd has always been left behind in terms of long-game tabletop miniatures. Mage Wars is really no different. People can't get together and run a Warhammer tournament in 3 hours. The same will be true of Mage Wars.
It makes the game less accessible, certainly, but the nature of design for the game kind of mandates this problem to the realm of unsolvable problems.
-nihil