i am currently buffing my plenum with Tripoli and then White Rouge. but there is alot of black\grey stuff on the buffing wheel that i am using the Tripoli on. is this normal? also how often should i apply the compound??

and when i try to apply the white rouge to the loose flap buffing wheel. it seems like its not getting on the wheel. and there isn't much of a difference between buffing with Tripoli and White Rouge. its about the same and i can still see scratch marks, and im not sure if they are from the buffing compound or if i should go to a higher sanding grit, i stopped at 400.

also what is the easiet way to buff the runners? i can't get in between the tubes with the current wheel that i have....!!