Always good to tune lambda instead of AFR as you don't get confused with different fuels
~9.8 is stoich for E85 so 9,5-10 AFR would be a bit lean.
Tuning lambda with E85 is basically the same as with gasoline, so shoot for 0.85-0.9 for best power. I've done back to back lambda variation tests on the engine dyno with E100, E85 and gasoline on different operation points on different engines and the behavior is basically the same. Benefit of E85 is that it holds power better in the richer ranges (lambda <0.85).
For the same lambda you need ~40% more fuel volume, so you probably have to upgrade your fuel system.
You also have to consider, that with the high ethanol contend E85 behaves very similar to pure ethanol, which leads to the fact that it has a more or less fixed evaporation temperature than a wide range as gasolines do. This leads to the problem, that you have to tweak your cold start and warm up corrections quite a bit to get a good fuel precontrol for the lambda controller. Otherwise you will get into drivability problems during cold start drive off situations and with a cold engine in general.
But apart from that minor thing it is amazing stuff. You will be surprised what ignition angles you can calibrate without getting into knock. If you don't have a dyno on hand a good aproximation where to stop with the ignition is the KFZWOP tables as they contend the ignition angles for best power (on gasoline though).
