Octane boosters are snake oil. With that high of a compression ratio, you will need 100% VP-110 octane racing fuel.
E-85 will not work for you. E-85 is equal to 100 octane but only if the fuel delivery system is twice as rich than used with pure petroleum based gasoline. That is because alcohol has a cooling effect and less heat release (energy per volume) in order to reduce detonation but only if it is rich enough. That is why E-85 has a false economic value and is not in general use.
The production of E-85 as a fuel is just to make the corn farmers happy by giving them another market for their product. About 80% of corn production is used to make chicken feed for all the chickens used by "The Colonel" and other fast food establishments.