If you're taking a class from an instructor who only recognizes a dual bladder as an appropriate redundant buoyancy device then you're missing out on a lot of options and overlooking some obvious drawbacks of a dual bladder system.
Ahhh! Thank you. I only know what I have read so far. I have not yet talked to to my desired instructor about requirements. I would be wasting his time since I am not currently the master of my schedule.
I'm hoping my SMB qualifies.