I leave my needle valve connected to my O2 first stage all the time. I disconnect the hose going from the needle valve to the head for storage. I just use the threaded LP connector because I have a shutoff on there too and I don't want to be sliding locking collars back and forth on a BC or omni connector by accident.Thanks for the fast responses!
Yes its for travel purposes and storage in between dive. I have a omni-swival QD that i removed from my DIL side, w/ a check valve. I could put it before the shut off valve, and try that. the BC quick disconnect isn't something I thought of for this, I can try that out also if the other QD I have doesn't work.