I have used a bunch of these adapters for a variety of lenses ranging from the SubSee to the SMC, to the Dyron to the CMC. The adapter that I now use almost exclusively for 67 mm threads is the Nauticam adapter. I am using it now on a Subal port (67 mm thread) but there are some 67 mm ports for which it won't work if there is a significant lip on the port. The Nauticam is a two piece adapter, one piece holds the lens and the other is a ring that screws into the port. For ports that don't take the Nauticam, I have used the Saga adapter. I have several of the Reefnet adapters but almost all of them have weak spots and several have broken (some multiple times) since they are 3-D printed. I have not tried the IDAS version but I like flip rather than rotate. Alternatively you could get a good machinist (Bill Libecap perhaps) to make you your own custom one but it might be nearly as expensive as the SAGA.
Cheers
Bill