On review using the Buoyancy Calculator spreadsheet over in Equipment -> BCs, it is evident that with a steel HP 100 and a wetsuit a complete loss of the wing will result in being about 12# negative even after ditching the weights. This condition occurs at the beginning of the dive, with a full tank, when the wetsuit is compressed at depth.
So, how to provide backup lift?
I'm trying to think through where I'd need this... I jump off the boat into a bottomless void and my BC instantly blows up and I am unable to drop any weight and am not in good enough shape to swim up 12 pounds...