I am still new to diving dry, about 50 dives on my dry suit so far, but yes. I find using my dry suit for bouyency control and comfort is the best for me. My experience is limited however to diving in the NW OH area quarries/wrecks.
I found a section in one of the manuals that came with my dry suit. Specifically it's the user manual for the SI tech dry suit valves. The picture should be attached. It tells me to keep my BCD empty during the dive.
That being said, you have WAY more experience than I do diving, just like my instructor has WAY more experience than me as well. So I usually defer to the experience to become familiar with the material/procedures/conditions and then when I am comfortable tweak as required.
That refers to the dump valve and it requires you to know where your valve is set, how it acts with your undergarments, know your body position, and seems to say that control is automatic with that valve. It's not. You have to get familiar with it. I've seen that manual as well and feel it's a bit misleading as to what the valve does. It seems to generalize the idea and does not get into what to do if you're still sinking. It also doesn't tell you that you can ascend at a rate that the valve will not handle the amount of air trying to escape from it at a fast enough rate.
Ideally the amount of air needed to offset squeeze can be enough to maintain proper buoyancy.
However, the risk increases when you may have more weight than you actually need and you have reduced the squeeze to where it's comfortable but you are still sinking. Are you going to add to the bubble in the suit when it's not necessary? Why? Add a bit to the BCD and you don't have to worry as much about the one in the suit shifting around.
If you start to ascend, as a newer diver, what are you used to doing? Probably dumping air from the BC. Good. Do that.
Then adjust the dump valve on the suit and make sure you're in a position where it will actually work.
A smaller bubble in the suit and in the BC is not beyond the abilities of the properly trained diver. If it is, I'd question whether they should be a drysuit to begin with.
Get your SDI Drysuit manual and open it to pages 86-90.
When we were writing the manual, one of the training department staff was in contact with several drysuit mfg's. None of them recommended using the drysuit for primary buoyancy. We also recognized that the new suits/undergarments may not require as much air to relieve the squeeze and stay warm.
The air in the BC is easier to manage than that in the drysuit. Which is why we recommended keeping the air in the suit to a minimum and using the BC as well when needed for added buoyancy. I could not use my suits for primary buoyancy on most of my dives. It'd require putting more air in the suit than was necessary and for no added benefit.