I am looking to gear my 99 MXZ 600 for a bit more jam in the 1/4 mile, any recommendations??

stock is 24/43. *try 23/43, you can use the stock chain. this is what I run and it does seem to pull better.

You could try dropping a tooth lower on the top sprocket.Your stock gearing should be 24/43.Why don't you try clutching it also?Someone on this site should have a set-up to pass on to you or else check out some of the aftermarket kits.

How much do you weigh? Is she stock? What is the lug height?

I weight 250, and the sled is stock! Would *22/43 work well? Would I still be able to use my stock chain? Thanks Guys!

I also forgot what width should the gear be? 11 wide or 13 wide? or..is it 25?

I would go with the 22-43 and think heavy on a 21-43.
Your 72 link chain wont work for either gear so get a 70.
Your gear and chain is called a 13 wide.