ORIGINAL: errolw98
If you wanted a synthetic oil instead of castor or to make a blend, I guess you could go to your local Motocross bike shop for your favorite synthetic oil as well. Is the price for Methanol and Nitro resonable?
I pay about $2.75/gallon for MeOH and about $30-32/gallon for Nitro. I think that is about average. If you buy more at a time, you get a better price.
I'm sure any Motocross 2 cycle synthetic would probably work but since the synth is the most "iffy" part, I tend to go with a synthethic I know will mix with alcohol and is used in racing or has at least been proven in that application.