RE: 2 vs 4 stroke fuel
I always use some Castor in my fuel. If it is not a blend, then I add it. And I use the same fuel for 2C and 4C. Had a very knowledgeable LHS say that most of the stuff was the same, just the color and label changed. Yes, there are special fuels but I have never had a need for them. I run mostly 15 Nitro fuels, I use Ritch's Brew, Morgan Omega, Bryons, and Power Master.
Cheers,
Chip