to me its worth it to jsut run straight race gas
the race gas is 4.25 a gal and pump premium is like 2.00
so a mix will cost you 3.15 a gal or so
but by the time you buy premix to go in that a 5 gal can will cost you
about 15.75 + 3.50 for premix=19.25
and 5 gal of straight race gas is 21.25+3.50=24.75
worth the extra 5 bucks a can to run it straight
just for added assurance
and race gas will almost never leave varnish in the bowls of the carb evan if its sitting around for awhile