I guess I was using the focus ring improperly, all those years. Whatever, it looked pretty good once I set things up. If memory serves me, I did have to refocus the projector slightly when inserting the lens, but perhaps that was because I was setting the ISCO's own ring improperly. I defer to a present user.
I'll check it out for you if I have time. It's a pain with my present projector mount, though. Sorry.
Trying to figure out what these go for on ebay, then probably willing to sell.
(To those of you have sent me messages, sorry for the slow replies, I no longer spend my days at the forum, been playing in my band, instead.)