Just a little tip to help you nail those jump kick sais.
Pre-buffer the sai motion:
Up, foward (to jump), away, towards, kick then punch.
Negative Edge:
hold punch, jump foward, kick, then quickly press, away, towards, release punch
On another note, I think you need really good execution in this game because of the all the memory of inputs. I was testing out combos with leaping bite and would often get the sai. Maybe negative edge is getting in the way.