For what it’s worth, non ethanol gas makes about a 20% improvement in mileage over 10% ethanol gas. Where I’m at you generally have to go premium to get non ethanol gas and that is generally about 20% more per gallon. I don’t really save any money but I get 20% more range. When my 200 was stock, and I drove 65 mph, I could get 20 mpg on the highway. Of course I only drove 65 once as an experiment...
The DOE states E-10 has about 3.6% less energy compare with ethanol free gas. I see closer to 10% in a 200 series after dozens of fillup of each (consecutive fill ups of each). I have the same issue (premium only ethanol free is the only ethanol free option) and it is 20% more. I only put e free gas in my carbs, but am fine with e10 in the cruiser if convenient.