33 on e85 and 36 on race gas.
I test this in engine dyno.
I was up on 38 on e85 and ther the power starts dropping fast. Backed down and it was the same power and trq on 36 and 33 so I run 33.
The VP motorsport 109 like the 36 better and made 10Hp more on 36 compered to 33.

This was on my motor i dont know what your motor like.