Yeah man....START with the PHGB. If the Airsal is anything like the 70cc Parma, then a 15 SHA will never get you more than 40's. You might also revisit the porting job you did on the case. I ported THE SHIT out of my case for the Parma and it flies.
And, obviously, the shaved head is going to help too.
My guess is that you'll have a mid 80's jet in the PHGB for that kit. Somewhere around an 86. Maybe 85. I think most of the Parmakits are happy around the low 90's.