Mostly I've been playing on a 60x60 with one armored and one inf. coy. Works well for me, I prefer a little faster pace anyhow
I think I'm going to go up to a 70x60 or 70x70 for my LC, however. The third Inf. company makes things too congested and close, though I don't want to add too much width right now, slow tanks and pedestrians
Matt