I suggest the mod sumore_v.tbm to learn balance. It isnt in the mod files (for some reason), but there's a public server of it, and if you want to practice with a friend go into private server and do /lm sumore_v.tbm.
This mod has -40 gravity, and everything DQs (even your hands) except for your feet. This way you're force to learn to stand up right, move around, push your opponent, on really high gravity while staying on your feet.
Lenshu is really good as well, but avoid gamemodes like judo or boxshu if you want to learn balance.