RE: 4 stroke fuel?
Use the Omega 15%, Cool Power 15%, Power Master 15%, etc. You want at least 17% lube, 18% to 20% is better. The 15% nitro has run very well in all of my four strokes. Saito 45 through Mag 91. I've got an O.S. 1.20 on the shelf and it will get the same.
Don