How nice would high octane gas be?

I haven't had issues with ethanol corrosion since I don't let anything sit with gas in the tank for more than a season or so (6 months?). Oddly enough I have also NEVER experienced any sort of rubber corrosion in the fuel systems on my '70 Duster, '88 5th Avenue, '93 Jeep Cherokee, our 12-year-old snow blower, 8-year-old lawnmower, whatever... However with the dry thin air here in CO fuel percolation is a BIG problem, worse than in other places with denser more humid air. If you have a carb'd car even with all the heat shields and spacers you can fit under the carb, if you let it heat soak more than 15 minutes there's no way it will hot start without holding the throttle open and cranking it for a long time to clear out all the gas vapors from the intake. That's really my only gripe with E10 fuel. There is a gas station that sells non-ethanol 91 premium, I may give it a shot in my '88 5th Ave because it has the factory Lean-not lean-Burn computer with knock sensor which advances the timing based on fuel octane.