This thread could use a bump.
I recently took advantage of revenuecollector's Germany giveaway (
https://goscf.com/t/43375). When I received the stamps, I broke out the Scott Classic Specialized catalog to identify them. When I got to the 1923 hyper-inflation issues, Scott noted both flat press and rotary press varieties. I wasn't aware of printing method differences with these issues, so I opened my old Michel Germany specialized catalog to learn more. The rotary press versions are slightly wider and taller than the flat press issues.
I dove into my duplicates too, to identify the flat and rotary press issues. Then I created a couple of album pages to mount them all.


I don't have them all, but I think it's a pretty good start. Some of the color varieties are a bit pricey, at least according to my 1986 Michel.
I enjoyed researching these guys, and I think I have a couple more envelopes to search to fill some of the holes.
Robert
Edit: Re-uploaded images.