I dive a whites drysuit in michigan and I have to tell ya, that if you are diving with a single cylinder, then your drysuit becomes your BCD thats the way it is!! You have to start adding air to the drysuit after about 10ft of descent, and between the about 100lbs. of lift that my drysuit can provide and the 45 of my wing on my backplate that amount of air to just get rid of the "squeeze" on my suit just trims me out perfectly. I was trained by SDI/TDI and IANTD and they advocate this kind of training, I also know that NAUI advocates the same thing. When I come up to about 20 ft I have vented all of the air out of my drysuit and I am back on the wing on my bcd but till then the BCD is only a back up. Though when I am diving my double steel 130’s and 80 al stage and 40 cu. ft. O2 bottles for deco then the wing gets more excercise deep because I would have to inflate the drysuit so much that I would look like the michelin man, but that’s a different story.