Brad,
One other thing to remember...
The wide band oxygen sensor actually measures Lambda, the ratio of actual mixture to stoichiometric mixture and it doesn't care what fuel you are running (100% gas, 95% gas, 90% gas, E85, alcohol, etc. i.e. it already accounts for the percent alcohol. The display device can be programed to show Lambda, or A/F based on the stoichiometric ratio you input.

I still like to talk in A/F ratio. So I convert Lambda to A/F based on 100% gasoline stoichiometric ratio of 14.7, this is called using the gasoline scale.

Gas: Lambda 0.85 x 14.7 = 12.5 A/F
E85: Lambda 0.85 x 9.76 = 8.3 A/F
Alky: Lambda .85 x 6.40 = 5.4 A/F
And E10 might have a stoichiometric ratio around 14.3, FWIW.

From running all those fuels, the "best" Lambda is not significantly different for any of those fuels. So leave your display in gasoline scale and shoot for 12.5-13.0