Looks like the 1 pc did not solve my problem, it only shifted it to a higher rpm. it now vibrates at 80mph and over which i suspect is 1/2 the actual critical speed. I took a road trip yesterday and the drive was enjoyable except at 80mph and over. Suffice to say i kept it 70 mph most of the time. I am gonna try to fix the 2 pc oems or maybe buy a GR heritage front half.
Worse still I suspect the U joints are not centered properly since mine is the staked on type.
Anyway to keep everyone updated, I got another guy to recenter and rebalance the old 2 piece, he claims its now centered and rebalanced, but he only is able to check up to 1500rpm. I tested the car and there is still a cyclical rumbling at over 70 mph, but i dont feel the vibration on the armrest.
I ordered a used untouched prop shaft set from Japan, will install once I get it.
The tire store also needs a road force variation machine, and knows how to use it. Too many places act like they can run their business like a McDonalds (here's looking at you Firestone) and they don't have anyone that can operate it. The short answer is the tire is rotated on the wheel to minimize vibration that occurs even when the balancer shows zeroes.