jets you're not going to know til you stick it on and run it. it should be a good top end power carb, don't think you'd want anything bigger on a 250. I dropped down to a 24 flatslide from a 26 roundslide (old suzuki 250) to enhance the bottom end. lost 10-15 mph up top but got what i need down low.
www.sudco.com
chad's the mikuni man at sudco, best person to talk to about setting these up, especially if you pick it up through them if ya know what i mean.