Mobile chars (especially Srams in that respect) don't have much of an advantage since you are unmovable, and gravity state 1 out of 2 turns I think. Any char is mobile in that fight since hitting a block (that shines) attracts you 3 cells towards it.
Use well-placed Cawottes whenether it's worth it, he always prefers to cast the CC damage spell instead of the -10 MP spell on 4 linear range, even if it's only a Cawotte that dies. If, for example, he is too much in the middle of the map and you place a Cawotte in a corner 7 range from him, you'll catch a lot of time. It might help to have all summons level 6 and low damage with Paralyzing so that you can easily buff yourself 2 MP if needed.
I can't think of anything else, the spell panel is far too one-sided.