I think I'm going to give your technique a try in terms of using the BC for buoyancy and the Suit for Warmth / anti-squeeze.
Steve W.
The secret is to start venting air BEFORE you need to. If you wait until You feel the need to exhaust the air, it may be too late. I open up my exhaust valve as I begin my ascent & start venting as my ears start crackling as the pressure relieves.I
If you think managing 2 air spaces is difficult,... try 3. With my rebreather & drysuit, I have to manage the BC (a wing), the drysuit & the rebreather's counterlung.