I too am wondering if this will be an issue in out NEAR future, and did some investigation into the usability of auto fuels. My Superior 160 HP engine is OK for 93 octane unleaded auto gas. The 150 HP with the 7 to 1 is also OK, and you can run a lower octane fuel in that engine, but I am not sure of the Minimum octane. A long discussion with Superior a couple of years back confirmed this, and the general rule of thumb was no auto fuel if you have compression ratio greater than 8.5 to 1. for the 160, Superior also recommends retiming to 22 degrees BTDC if you will be using Mogas. I thought a lot about the 160 HP 8.5 to 1 engine that I have going into my RV9 project. I decided not to derate it to 150, based on the hope that there will be 93 octane auto fuel sans the ethanol. So far, that has been available here on the NC coast at most of the marinas.
I am sure others will chime in on the subject with vastly differing opinion, as there seems to be much current discussion on the subject.
Hope this helps,
Chris