Sedate,
I'm not sure I understood Your questions correctly. You flushed Your sinuses with water to avoid having to equalize. Is that right?
Yes, filling Your airspaces with water will eliminate the need to equalize them (because then they're no airspaces anymore
)
The next barrier You'll reach will be Your lungs which You don't want to flush, I assume. They will be compressed to their residual volume at a certain depth. For most freedivers that would be somewhere below -30m.
At least some of the very deep divers used to do that, because people hadn't thought of things like the Frenzel technique and the mouthfill at the time.
EDIT: Ah, and why do You want to reduce Your speed of ascent? If You have trouble with buoyancy, You should double check how much weight You need. Carrying less air with You will certainly not increase Your buoyancy, anyway.
HTH
P.S.: welcome back!
