The most common procedure for balancing a diaphragm spring pressure plate is to weld a short piece of round stock to the cover, sort of like a wheel weight. The Borg & Beck style pressure plate has a series of holes drilled in the cover, and a slug of Mallory metal (heavier than lead) is tapped into one of more of the holes for balancing purposes. Spinning the flywheel and clutch cover is a good idea- - -including the disc isn't, because there's no way to predict where it will lock up when the clutch is engaged because it's splined to the transmission input shaft.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!