Some progress- the distributor is back together again. The gap still needs adjustment and I'm still looking for my plastic gauge (I suspect it's out in the shed and I won't be able to get to that until the weekend) so the distributor hasn't been reinstalled yet.

I did slice out a 'window' on the ruined cap between two plug wire terminals to check the gap with the corrected end-play and the new rotor with the .060" longer blade and it fits great- a much smaller gap than with the original rotor, and the rotor tip misses the bases of the plug wire terminal posts by at least a 1/8". So it looks like the original problem is taken care of...

Hopefully when I find that gauge I'll be posting again this weekend to report on any changes in the engine....