Just put the wheels as wide as they will go, set all for 12 psi and try not to make any sudden moves your first track session. I’d suggest you run RedLine kart oil at 32:1 as you won’t have to worry about going through the tech tent for a while. Don’t know what gear you have on the front but an 85 rear gear would be a start. You sure jumped into the deep end with a Rotax as your first kart. Are you local to Millville? Sometimes I help people at the track, let me know when you’re going. Below are some vendors I have used for Rotax and general kart stuff.