ALWAYS run at least 93 octane premium. You might experiment with a 50/50 or even pure 100 octane race gas also, although anything much above 100 octane may well be overkill unless you have a higher than stock compression ratio. I use Honda HP2 full synthetic racing 2-stroke oil at 32:1, the bike runs very fast and clean.
Although it is trendy to use a fancy aftermarket oil ($$), Honda synthetic oil is extremely good and a little cheaper than some aftermarket brands also.
And don't put around too much on a 2-stroke MXer, that will tend to lead to more frequent fouling.