As I understand it, ethanol replaced MTBE in gas and the unintended consequence was phase separation. Non-Ethanol fuels will still have MTBE but they are being phased out.
For the past 22 years, I've followed the same route as most. Every winter, add some Sta-Bil (and/or Marvel Mystery Oil) and fill the tank to prevent rust, and change the oil and filter before storage. I typically have not run the car in winter unless I can drive it and really warm it up. There is a lot of moisture up here in the winter, so running it just in the garage does not necessarily do the job. I may keep it insured for the road all year long this year so I have the option of taking it for a drive on nice days, which I used to do as well. Years ago, I also saw a video from "skinned knuckles" magazine about pouring Marvel Mystery Oil down the carburetor to lubricate the top end of the engine, and basically pouring it until the engine stalls. I did try that once or twice, but I don't do it every year as it gets a really smoky for about 20min during spring start up until the MMO burns off. I guess it really does coat things as planned!
I had been thinking about this awhile as I don't think I have non-ethanol as an option, but something occurred this summer with my daily driver that got me really concerned. My DD takes premium fuel as well and I had to add a bit of fuel in a small town. The car ran well for the rest of the day, but the next morning, the car would start but run poorly like 3 of the 6 cylinders were dead and then shut down. It did this a couple of times, so (after I checked the fluids) I just put my foot into it and revved the engine on start up. It choked for a bit then smoothed out and idled normally. I spoke to some local boaters, who are the primary users of premium fuel in this area, and they said that water in the fuel was quite common there as the premium gas sat in the tanks at the gas station longer than regular, which was likely my problem. At any rate, this isn't something I want to experience in March when the car comes out of winter storage. I'm not so worried about the lawn mowers as I already run a bit of MMO with the fuel in those and I typically run them out of gas every fall anyway.
I've purchased a bottle of that Ethanol Shield and we'll see what happens. I may also try the MMO trick again this year to coat the inside of the carb. I'm definitely going to have a full tank of gas, but I'll work a bit harder and try and burn it faster (which isn't difficult to do in a Big Block Buick!).