seems like cascade loves 28mmpwk's. they put 28's on my buddies bike (oregon banshee) and he's got a 4mill. i think they do it to keep bottom end. those 28's should work well with your setup though, dont think you have too much motor. i run 33's on my duneported bike, but i noticed some loss in bottom end when i switched from stock to these. however, the gain in top end was well worth it IMO. main reason i went with the 33's is because i plan on goin bigger with my motor in a couple of years and new i would end up getting larger carbs anyways.
my riding style is 60% duning (2nd to 4th gear mostly), 25 % tree shots, 15 % dragging.