Can you tell me which self-timers actually work with prewar - Fed1 cameras?
I do have the original FED selftimer (with the mirror) but I would like to have some less valuable and more reliable alternative for actual photography.
I don't know all the Russian selftimers. But I think most part of them fit post war cameras (Zorkis and Fed 1f-2nd series- and 1g): their release buttons were modified in that purpose.
I went to Leicashop today and bought the APDOO, works great.
The only thing I noticed was that it seems to struggle quite a bit to provide enough pressure to release the shutter button, I guess you need less pressure on a Leica. The original FED selftimer has no problem with this but as you said it is by far too valuable to carry it around for photography.