What Size would I need to protect my BCD,Regulators & all the other Dive gear?
Can't really answer that. We used ours for photo gear.
You will have to lay your gear out as you would like to have it packed in a case, maybe add some volume for future growth, don't forget if getting dividers they take up space too.
Sorry, not much help.
Furthermore if you want a almost bomb proof case to protect your gear and travel allot the Pelican cases are the way to go. When I travel I hand carry my reg set, I dont trust the baggage handlers slamming my reg ( ATOMIC T-30 $1700 reg and worth every penny
I have the 1450 case and use it for my very pricey camera, housing, strobes. A Pelican case for your dive gear is usually not practical unless your TEC-REC, military, etc. My dive gear bag is a AQUA-LUNG, I also have a Mares, both have the room for 2 sets of dive gear and special pockets/ compartments for your reg, fins, mask, most BCD. If you really want a Pelican you would need one 10 X bigger than this one and these cases are not cheap, at least for me anyway. Hope this helps. Kamuela- Hawaii Master-Scuba Diver, Sidemount, Tec - Rec CCR diver
Sorry, can't answer your question. I got it for a DSLR in 2011 and I'm very happy with it. Good padding and watertight; exactly what I was looking for.