so far the most damaging version from my exp is this
vc1: fierce fb,s.rk,fierce demon flip,strong demon flip until corner, then s.fp,whiffed fb etc
i know doing his demon flip otg at the start will always be the most damaging, but i cant get the timing 100% right 
Most damaging : add-in HP for the first hit .
Also , if you do the corner reset , I think it is even more damaging , because he can’t escape .Even if you stop the combo , you begin another in the same style for about 2 seconds later ^^
how does the corner reset work again
Even though I am not pro ,I have some level at versus casual .So I can help you .
Corner reset :
when you do HP x whiffed FB , instead do HP x back 3K teleport .Then do a fierce fireball , fierce demon flip , lands with K version , THEN 2 LK x into Fireball .
That’s easy .