Thanks for the link, fflupo.
Sebastien Murat's method is very interesting, and backed up by a lot of scientific explanations.
However, I still have my doubts about the safety of exhale diving. The issue of water entering the lungs during a blackout or LMC is one of the things that concerns me. Another is negative buoyancy. I am very buoyant with full lungs, but negative even at the surface on full exhale. This would make getting to the surface that much more difficult in case of trouble.
