Ok update:
Stacked both units together.
One out of the parts tractor measures about .050" clearance between drive and driven:
One out of the tractor is no clearance as it was when it was mounted on the motor (picture is showing feeler gauge not going between the drive and driven):
And just for fun swapped the drive plate from the parts motor and the driven plate from PTO out of the tractor. Clearance is about .130". So I understand why you don't swap parts between the two. The magnet is probably not strong enough to overcome the springs when they are displaced that far already.
There is a decent amount of wear on the back of the driven plate from the parts motor. As the bearing feels a little tight. I will try to clean and degrease see if it improves.
Any other input? All input given this far is very much appreciated.