running 12/1 comp or better, with E85 being 105 octane, err better to say, 100+ octane year round....
high compression would work in a dedicated E85 fuel, daily driver auto.
granted E85 cost compared to 87 octane is a major factor in making it worth it. the other thing is, is the fuel even in your area
let alone the cost of doing the compression change.....
making a dedicated E85 fuel auto is something that's on my bucket list, not any day soon....
with a much more common un modded, 9/1 comp engine running 100% 87 octane gas with no ethanol in it, will get you the best cost per mile.
9.25 to 10 compression, is for the most part, the limit of 87 octane in most engines. but there are getting to be more and more modern VVT engines now days.
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1 86 T\D trooper with rare GEN 3 rods
TRANS FIXED 
NOW DD
1 86 4WD 5sp pup is 2.3L gas, but plan on 2.2L diesel repower
1 91 trop, long term plan is a group buy of imported Isuzu 4JB1-T 2.8L I-4 engines, hoping to get price down to 2K not 3K plus
1993 sidekick my MPG toy, epa rating 26.
i get 29/31 with stock drive train.