Extreme clutch shudder

Ron816 said
......the clutch I had installed was A Borg & Warner clutch from Brewers, I decided to install a perfection clutch which was to OEM specs, well it worked no shudder nice and smooth

Can you measure around the B&B disc with a caliper? If it's flat and the hub isn't bent for some reason, all that's left is the plate.
FWIW, MP provides this finger height jig (less specific instruction)............