I think it depends on the track very much. I ran a whole day damn hard with one setting at a medium-sized track and then blew the engine riding home calmly on the expressway.
If the track doesn't have monster straights, and you're not hitting top gear for long then you probably have less to worry about than you think.
If you're geared long and have big straights with time spent in top gear then it is really important to get the (main jet) jetting right. If you're not using premix then you can just add a capful or two of oil into the petrol tank.
_________________
MC28 SE -sold-
MC21 with RS250 engine -for sale-
MC21 race bike -soon for sale-