I have recently had an alternate theory on this subject shared with me, but the individual who researched it does not have access to some documents at the Rakow which may provide the final pieces to confirm it. In the near future, I am going to request some documents from the Rakow on an inter-library lend for microfiche relating to my Welz research, and I am going to include the documents needed by the individual doing the work.
If there is validity to the theory, which at this point seems reasonably plausible, the information will be posted in this forum. So this may actually not be completely solved yet....