I suggest: each player starts the tournament with a pool of 8 positions (2 of each faction, for 8 games). At the beginning of each game, the player chooses a faction from the remaining pool and informs the judge (it is then removed from the pool). This way: 1) players will think about which faction to use immediately (strong/weak factions) and which to save for later; 2) knowing the opponent's pool, they can think about which faction to keep for themselves. I like this much more.
I suggest: each player starts the tournament with a pool of 8 positions (2 of each faction, for 8 games). At the beginning of each game, the player chooses a faction from the remaining pool and informs the judge (it is then removed from the pool). This way: 1) players will think about which faction to use immediately (strong/weak factions) and which to save for later; 2) knowing the opponent's pool, they can think about which faction to keep for themselves. I like this much more.