Just my thoughts on the numbers.
I think 12 is the optimum here, but I agree with most of you that 12 is quite hard to get together, I’m currently the leader of The Blood Sacrifice -[BS]- and I’ve only got 9 players at the minute.
So would it not be possible for 3 leagues of 8 v 8, 10 v 10, 12 v 12?
Each clan is allowed to field a team for each league?
As far as class distribution, I think specifying that 2 of each class must be played and no more than 3 archers would work nicely for all the size groups.