I like that idea about a bolt snap on the primary hose to just keep it clipped to something when not using the gear so it's not just dangling. What size bolt snap is best for that?
LOL one thing I've noticed buying SCUBA gear is that damn, EVERYTHING comes in like 100 different sizes and I have no CLUE what to get size wise most of the time.
For the 2nd stage hose, one typically will use a small bolt snap
DGX S/S Swivel-Eye {2.75 in | 7.0 cm} Small Sliding Bolt Snap | Dive Gear Express®
Look at the bottom of this page for a guide to common diving applications of the different size bolt snaps they offer:
Premium Stainless Steel Snaps | Dive Gear Express®
-Z