for a subborn sprocket might be that the puller (gripper) bolts don't grab enough? Might need to drill some kind of shallow grip hole (craters) in the sides of the gear so the puller screws can grab better?
FYI -- I used the steering wheel puller on mine (it was badly rusted to the crank) -- had to ratchet the damned thing pretty much all the way off. Tapping the screw holes actually went pretty fast -- but I did get a fair amount of metal shavings on everything.