I'm not going to claim it's correct, but here's how I pronounce the agencies I'm aware of using common words (or names) instead of phonetic symbols.I've sometimes wondered how non-English speakers pronounce the names of the various three-letter agencies. It would make sense to me that they pronounce the letters as they would in their own language. Similarly, should I pronounce "CMAS" as a Frenchman would? I'm not sure there's any alternative.
CMAS see-mass
BSAC BEE-sack
PADI paddy
NAUI now-wee
RAID raid
ANDI Andy
PDIC pee-Dick
IFDI if-Dee
For the following, I just say the letters
SSI
SDI
TDI
GUE
ISE
NASDS
YMCA
UTD
IANTD