The link to the thread the OP referenced, the guy with the 11:1 CR started out the engine on Premium gasoline for 6 months before going to E85. It would have to be pretty "middle of nowhere" to not be able to get premium. I lived in Delta Junction Alaska for several years. More remote than most folks on this forum will see, and we had Premium available. Bit of a stretch that he would be locked into one fuel.
That is why I like my Flex Fuel Silverado. When combined with a Diablo tuner, I can set the high performance 93 octane tune and use two different fuels, premium and E85. If either was not available, just switch to the 87/89 octane program and can use regular, E10, or E85.