After an afternoon of jetting, my shee, with very similar mods as yours, seems to really like 280 mains with a 30 pilot, needle clip in the second notch from the blunt end. I was experiencing the same kind of bog and sputter you are, and the pilot made the difference. You'll definitely wanna go up from stock!! Hope this is a good starting point for you!!! Oh yeah, gearing is not gonna help your problem out, by changing to a 13 it'll just sputter for less time, and give you less top end...won't fix the hesitation though. I run a 15 tooth front and love it!!