It's all about the jr. depth restriction. The Brac and LC's walls could be an issue. We did go deeper as our DM took us to shallower dives first and saw our son was an excellent diver. We just went with Brac Reef Divers as there wasn't any other op on island at the time. My wife had found a house first on VRBO, Cayman Brac, where's that? lol Thankfully Martin (who ran Reef divers for years) was just in the process of setting up his shop and wasn't even technically open (permits were in the works). So had to use a smaller boat but it was just the 3 of us! However the weather wasn't great so we didn't get to dive as much as if we had a proper dive boat-he's got one now.
The 63's are helpful but we've always ended up strapping him with the 80's. He uses as much air as I do, he stays close but never stops darting around!
In Salt Cay there was never an issue from the start but in Provo I had to make 4 calls before we found someone we could dive with. Our top choice was "full", 2nd wanted us to hire a guide for him, 3rd gave me the 3rd degree about his deeper dives in the Brac (get this-they had a TA review about a jr diver running out of air!), 4th was charter only (newyrs week-$1600/day!!!) and FINALLY Dive Provo was cool.