ethanol and octane are not related, octane is the rating method for the gasoline the alcohol is mixed in to- before it is mixed'
the alcohol can be thought of as a magic liquid that disappears without leaving a hint of it's when it burns non e will get you more bang for the, squirt that goes in , as alcohol is kinda bangless compared to gasoline. i get 5 to 7 more miles to the gallon with non e and my small engines run better. ethanol at higher concentrations than 15 % is corrosive to rubber and aluminum, only mildly but,,, remember what ethanol's purpose is? to supplement gas from alcohol, if it were viable as a fuel we would have increased the % a long time ago. ethanol has fewer btu's than gas per volume, btu's is what makes the engine go roundy