@viridian That 10cu was measured as all japanese cartridges at 100hz so at 10hz means over 15cu. Btw, I owned that Onyx and the Black and Rosewood too.
I think that my first MC was the Denon 103 with 5cu that means over 8cu and my tonearm in those times was a Pioneer in the PL 630 that was away to be a high mass tonearm.
Anyway, was and is part of what you and me learned and it's ok. No problem.
R.