Jetting For Mod 98 Rmk

I just bought a sled 2 weeks ago and unfortunatly blew it up last week. The guy apparently didnt know what he was talking about and told me the wrong jets were in it.

So here is my problem....getting it jetted properly so once I get it all back together it wont happen again. I know a little about main jets but nothing about nettle jetting and such. I have been told that needle just take effect from 1/4 to 3/4 throttle. I switched out the 185's that were in the machine and put in 220 and 230 on the mag side. I was told that the mag side in these sleds runs hotter...which makes sunse because thats the side that seized on me. As far as I know that is the biggest main jets they make for keihin carbs. Ok so now for the tricky part...the mods.
It is a 700 RMK, but because of the blow up it is going to be bored out. Should be just bored to the big bore of I think 756 or something like that. It has twin CPI pipes. SLP Cheater Heads. It also has a track entension to 151 (dont think that makes a difference.)
I will be running it at pretty low altitude...(400-1000ft)
and in pretty cold weather (20 above to 20 below)
What kind of adjustment should I have on the carb to run? How do I adjust my needle jet?

Thanks a ton
Carl