Go to motorcycle shop and buy a quart of Maxima 927. Mix at 5 oz to gallon for first gallon then 4 oz gallon thereafter.
I use empty dry windshield washer plastic bottles to mix and store my fuel. Add oil first then add 3/4 gallon of gas. Install cap, tighten, and then shake vigorously. Add remaining gas to get full gallon. Store out of sunlight.
Before the safety klan says anything, the windshield washer containers are the same containers that house model airplane fuel. I've been using them for gasoline for years without any problems.