I always run AmSoil Dominator Racing 2 stroke oil in the fuel.
If it's winter (35-55 degrees) I run 40:1
If it's spring/fall (55-75 degrees) I run 35:1
If it's summer (75-95 degrees) I run 30:1
I do this because I don't like tearing my carb apart to cahnge the main jet or fooling with the air screw.
Another option is to jet your carb during the spring/fall on a 65 degree day at a 35:1 pre-mix with a vented air box lid, the run a closed lid during the winter and no lid during the summer and always run the same 35:1 mix.