Whatever next?

[Tony Press]

Tony 

Ball race at the rear, with a spacer ground to ensure the crank can't float.
No lip at the front and two ball races. Has worked perfectly for over 15 years. All the restraint for crank thrust movement from the clutch is done at the rear of the crank, which is probably how should have been designed anyway. As you say, 1.5" crank helps

C

This would entail a huge amount of fitting work to ensure the bearing inner ring was 'nipped up' at the same time as the flywheel was nicely locked up on the taper.

I cannot imagine the factory expending time on this !

I would have thought floating two ball bearings in the alloy housing may have lead to wear but you seem to have got away with it for15 years (racing or road use ?)