Boltsnap on 2nd Stages

[NDonahue]

Feel like you have this backwards. A more streamlined setup would be putting your backup regulator on a shorter hose on a necklace. Put your primary regulator on a longer hose (40" is pretty common for this) and put a boltsnap on it (not a suicide clip) for clipping off when you're on the surface. In an emergency, donate your primary to the OOG diver and switch to your necklace regulator. If you need to blow an SMB, switch to your necklace regulator and use your primary and then switch back when you're done.

This is the setup I use for my son as part of prepping him to eventually move into tec. One suggestion to OP: use a zip-tie and old o-ring to secure the bolt snap to the regulator hose. If for any reason its clipped off under water, this makes it much easier for someone stressed to break it loose in a pinch.