I have done about the same thing for the last 24 years without any problems. I have always used Prig-g gas treatment with every fillup. I rebuilt my carbs about three years ago. I found zero buildups of any kind in the fuel lines. I have always thought that starting out with fresh gas was the way to go.I start adding startron with the last couple of fill ups in the fall. Try to burn as much fuel off as i can before winter storage. Then put fresh gas in both tanks in the spring. Been doing this for 15+ NE winters.
Motorcycles... snowmobiles... generators... and whole slew of outboards running ethanol fuel. You're over thinking it - it'll be just fine. Besides, it ain't about the block - it's the rubber components and such that can suffer. It certainly won't hurt to use E-free, but there's really no need.I've always filled for longer storage in the hopes of less condensation buildup inside the tank. I had Hondas until recently and always used 87 and an ethanol treatment every time I got gas. Never had any fuel issues with those Honda 225s. I got Yamaha's now (250s) and haven't figured out if I need to get ethanol free fuel or just keep doing what I've done with the Hondas for over a decade. My reasoning was there are millions of Hondas on the roads burning ethanol fuel with no problems and the 225s have the same block as the Odyssey. Yamaha doesn't have any vehicles on the road so I might get ethanol free for them.