My advice is not to waist time, I agree with the other posters, unless you tune for E85, theres no real gains to it outside of it being cheaper than premium fuel. When you run strait e85 is a different story.
I can tell you that on my tune (1000cc injectors, Stock vf52 turbo, intake, fmic, and 3" turboback catless exhaust) I had my tuner do both an E85 tune and 93oct tune. Same boost levels (20psi becuase I didnt replace my BCS
maxed it out at 20) the E85 had 45 more wheel horse power and 40 more wheel torque just by running e85.
This is just my opinion, i do not reguard this as fact haha.