Morning Tom, Great score on that PL-7. Shoot me an email to beej1123j@aol.com and I'll fire off that disassembly/reassembly guide. Piece of cake (and some patience) to solve that speed issue. Cart-wise, the ultra-low mass tone arms love high compliance carts. Those AT entry level carts are more of a crap shoot than anything. If it were me, I'd mount that Denon on the PL-7.
Take care,
Butch