How much lift is really needed or is too much?BCD?

[mempilot]

You might be able to pull this off, as an extremely experienced advanced diver, with a cool head, and good arm and leg strength and technique.

I would not bet on a beginner doing this successfully, however.

You can forget about the lift bag issue. You won't have time to deal with a lift bag, for the real thing.

Like I said, you sound fine, taking care of yourself. But I would not bet on your configuration for taking care of students or inexperienced divers.

I agree that swimming a distressed diver to the surface requires a cool head and good technique. Beginner divers are not expected to do this, nor are they trained to do this. So that point is mute. My skills to do so are current and sufficient given my current rig configuration.

I tend to disagree with you on the lift bag though. If I have an unconscience diver at the bottom, I have plenty of lift in my rig to bring us both up without the bag. I can use their bladder, my bladder, or a combination of both to complete the ascent depending on condition of our equip. If my bladder is blown, but I'm rescuing another diver (bad day), I can use the bag to bring us both up if his bladder isn't fit for the job. Again, practice, practice, practice.

This has drifted off topic, and I apologize to everyone.

A 30# bladder will be more than enough for a recreational diver to do what he or she expects of themself under all conditions he or she should be diving in.