800ski, I can't give you a jetting change for your sled as it has flatslides and I don't know your stock jetting, but on my '97 Mach 1 with roundslides, I went up from stock 350 mains to 410's (this was with removing the shelf in airbox) when I had my Jaws trail pipes (which run at 9000-9100). As for clutching, my best all-around (trail, snow drags, & top end) setup was: prim. red (230-410), 286 ramps, 12.9gram pins, tra set @ #2., sec. beige, 44 cam set @ 18-21lbs. My gearing was 25-44 and I had a 1" predator track with 192 megabite studs. I found that the ultimax II belt worked the best with this setup but had to be well broken in and the belt wore quickly (got narrow quick), but I never blew one. You also must make sure engine and clutches are perfectly aligned, especially with high revving pipes. You should check with PSI for squish specs. with their pipes along with jetting, as I had to go to a 0.6mm base gasket to get a min. of 0.067" squish from my stock 0.056" squish in order to avoid detonation with pipes. Also, if you do alot of trail riding, mileage, and racing, expect to wear out crank bearings quickly.
Hope this helps !