I did my OC tech training in Florida, in a wet suit. The way we trained with redundant buoyancy in case of wing failure wasn't to shoot a bag and reel yourself up. We basically used the SMB as a replacement for the wing. Clip it to the crotch strap D-ring, inflate it the same way you would inflate the wing (little bit at a time), and if you overinflate you pull the dump valve. You also usually need to dump on the way up, just like a BC.
Other training agencies stress the idea of a balanced rig, and say that you don't need redundant buoyancy and that you should be able to swim your rig up in case of a wing failure.
I used a double bladder wing the few times I used doubles and a wet suit. Easier than using an SMB or a lift bag.