I converted my 66 lightning to a ball bearing many years ago. Rode it for about 4-5 years afterwards and sold it to Richard who still owns it I believe. The ball gives up some load carrying capacity but keeps the crank from shucking back and forth. Make there is a tad of clearance so when you tighten the case screw it doesn't side load the ball. I put the TS thrust washer back in but you can likely leave it out. The details area bit foggy for me after all these years but I think that is how it works. Someone correct me if I am missing something.

Mr Mke