I did a test with E85. I didn't figure out the ratios, but what I would do is put 4 gallons of e-85 in the tank, then top it off with 92 octane gasoline (10% ethanol blended).
My car has 60lb/hr injectors and had no real issues driving around. Adaptive appeared to be able to take care of it (this was before I had the QH and can see what is really going on) keeping AFR right around stoic when in closed loop. In Open loop, say WOT, the standard tune was unable to adapt enough to achieve commanded AFR. With 92 octane E10 (all gas in MN is E10, except for a select few) commanded AFR was 11.5 and the car could achieve that. With E85, command AFR was still 11.5, but actual ended up being more like 12.5 to sometimes 13.1.
Drivability wise, i was testing the E85 blend to combat some low rpm high load pinging (snapping to part throttle in low gear. my static cylinder pressures at low rpm are on the high side). for this, the E85 did cure the detonation at those points. And even though I was seeing 12.5 and higher AFR, I was not getting any noticeable detonation, but certainly it wasn't safe.
The BIG challenge with Pump E85 and tuning is that E85 is not a consistently blended fuel. To be called E85 in Minnesota, it can be anywhere from E70 to E90. My guess is that is the same in other states. And this blend ratio can change from one load to another that they get at the station. Thus if you are going to tune for E85 specifically, you will want to start super green safe, and only ease your way up to pretty green safe. You never will want to be just safe, as just safe with Pump E85 isn't really safe at all.
OTOH, if you want to tune it tight, Rocket Brand, and some other Premier fuel suppliers can supply you with 55gallon drums of E85 that is guaranteed to be consistent. (though there can be differences from barrel to barrel)
if you haven't seen this link, you might find it useful.
http://www.e85mustangs.com/tuning.html