Not really directly related to your questions but maybe of interest for some thinking of connecting Seacam strobes to Nauticam Housings via Bulkhead:
I installed two Seacam 150 strobes to my Nauticam Housing this year after bringing them back from the Dive Show in Germany. I got them with the Seacam Bulkheads as the Nauticam ones were not available at the booths of the various dealers at that moment. So i decided to go with the Seacam ones and use the M16-14 step down adapter that Pavel mentioned above.
The bad surprise: The Seacam M14 Bulkheads don't fit through the Nauticam Step Down Adapter as the thread is too long.
I had the adapter milled out and filed off the front part of the bulkhead to make it work.