[michaelbsc]

Wasn't Rollei Retro 100 and 400 cut and furnished in both 120 and 35mm size from the same base material (intended for 35mm)?

Yes, that's correct. It was a 35mm master roll that had not been slit into pancakes yet. So the deal was struck to cut it into 120 size and confectioned with backing paper on spools instead of in cartridges.

I still have an unopened box of it in my freezer. (I am not a hoarder. I am not a hoarder. I am not a hoarder.)

It's just a tad finicky to get on a Patterson reel, but once you get the hang of it there's no problem, and it feeds fine in any camera I've used it in.

MB