Well, as long as you know the rules it really only matters that your opponent agrees with you. I take liberties with the rules all the time. I used to deploy in the first two with the old maps, because I like the “movement to fire” part of the game.
Something like MechanizedWarfare suggested works best; US & UK vs GE usually works well. A free-for-all is interesting to do sometimes, but often it simply ends up with two players joining up against the third who doesn’t have a chance.
