Sorry that you had issues last time. What may have changed was the time that the ethanol had to sit and accumulate water. That's an issue.
I tend to think that a good additive mixed in properly with non-ethanol gas would last just fine over a six month period. Lots of old timers around here swore by Marvel Mystery Oil, and some would add a detergent. Before my relatives started using PRI-D and FP60 they used a detergent from Primrose Oil called "Injector Professor" that had been around since the 1950s and Marvel Mystery Oil. Their tanks were always clean. Then, they switched to FP60 instead of Marvel Mystery Oil, and later to PRI-D from Injector Professor. I think that the important thing is to dose properly, not to excess, and to use a good additive. Lots of people with bulk tanks just add a bottle of Power Service when they tank up and it's better than nothing by a long shot.
Whatever you use, even Star-Tron (with electrolytes, like Brawndo), call the manufacturer and ask about the rates for dosing bulk tanks. They may be half of what they would otherwise suggest and I think (with no real evidence, admittedly) that a lot of the bad rap that Stabil built up over the years was because people would use 800% more than they were supposed to and "it would gum up over the winter". Actually, they would add an ounce to a quart tank when they were supposed to use an ounce to a gallon, and unsurprisingly the small engine would run strangely for a while afterwards. You may be able to spend a lot less money and get perfectly acceptable performance with the blessings of the manufacturer.
