I bought the valve lapping compound at O'Reily auto parts. It came with two tubes, one was fine and the other course. Kris at Coldblooded said to just mix them in equal parts, smear a bunch on the end of the crank shaft and gently push in on the clutch hub in a clock wise direction about 25 times. You can really feel it smooth out as you are turning it. Be sure to clean both the crank shaft and clutch hub with brake cleaner very well. It de-burs each mating surface for a tighter tolerance. Blue Lock tight the bolt end, torque to specs then wait over-night and your good to go. I also maked the bolt head to clutch body with white paint to see if it has moved the next time I disassemble.
my only concern with compound is if you put it on the crank and then slide you primary on, it may be possible for some of that compound to get pushed into the crank shaft seal. if its does get to the seal, might start causing it to leak?