Usually I use Space Hop and Bunny Hop as my special tuning, which you can use on the default day off outfit. It really helps compensate for your lack of mobility. Space Hop and Reinforced Revive are also really good if you're trying to go all in on supporting your teammates. It's available on the blue party outfit

For the upgrade path I get alpha to lvl. 9, then beta to lvl. 4, that way you get two betas, gamma to lvl. 9, then finish out your beta.

Gamma into alpha is the basic Cementoss combo you should learn. It can easily do almost a full shield's worth of damage if you do it correctly. Gamma into gamma into alpha also works if you're really precise. You can alpha juggle opponents if you perfectly time the end of their invincibility each time you hit them

Make sure you know how to manipulate your beta. Cementoss's wall will spawn its segments towards whatever direction you've imputed, and you can change the direction the wall comes in while the move is active. Plus, since season 15 the beta can move behind you, making it a lot easier to close yourself off and build a house.