No, D-White does not count towards your pigment load. It is a balanced ink, meaning you can print and cure it by itself just fine.
I would image that it is at full pigment load on it's own though, so obviously won't count towards taking on more pigment itself.
We do quite a bit of mixes with the discharge white, but only if it will be printed alone or last in sequence.
The white spots are dried pigments. One of the tradeoffs for the beauty that is wb inks. Filtering through mesh (we use
hop bags from the homebrew supplier) will alleviate this. And good ink hygiene will help as well. Certain pigments are worse
than others.
I'm looking at a blade type homogenizer that spins at 45,000 rpms (most drills are ~1000 rpm max) but no one can
tell me if it will help with re-wetting dried particles.