Interesting that NAUI cave 1 and 2 don't seem to allow for CCR or sidemount either
This is the NTECH gear config (as was posted somewhere else)
No other config is permitted in NAUI cave1, cave2
"Twin primary cylinders connected by a dual-port manifold with an isolation valve are required for all training that will involve actual or simulated decompression stops. For training that does not involve decompression, a single primary cylinder with an “H” or a “Y” valve is acceptable."
SO...what does all this have to do with the OP's original statement and question, some 41 pages ago???