Thanks Ulrich.
About the extra hole in the speed wheel, it's a good idea. But I wonder is there will be enough space for the leg. Unless I adapt a slimmer leg borrowed to a Fed? Not impossible...
As it is, I noticed that the arrow on the clip is in perfect position for Z and 1/20th. But things are not "square" after: for 1/40th on the dial, it's between 30 and 40, and so on . Differences of regulation between Zorki and Leica?
About the lens, that's another chapter! I bought the camera with a Steinlein Cassarit made for the Braun Paxette: M39 too, but with a register of 44mm...

So, things are open. A genuine Industar 22 or Elmar? A fake Elmar, to keep the original idea? For the moment, I don't know. If you have other ideas...

Amitiés. Jacques.