@jacksky I don't have the scientific acumen lewn has brought to your dust dilemma. However, just instinctively, brushing records with felt does seem like it would cause static electricity and attract dust like nobody's business. Another reason why I would never use a felt TT platter mat.
FWIW, when I go through my ultrasonic cleaning process, I only do about 15 records at a time. That's, easily, an entire afternoon's worth of work, and then some, because of the labor-intensive process I use. I've tried a few approaches to keeping as much ambient dust off the records as they air dry (e.g. putting large high-quality microfiber cloths over them in the drying stand). Alternatively, I've toyed with the idea of obtaining a large rigid cover to put over them, instead, something like a humongous TT dust cover that I could find at a Michael's arts & crafts store or something along those line. Of course, a cover like this would need to be shimmed at the bottom in order to allow for some air circulation. Otherwise, drying would take a very long time.
I just accept the fact that there is always going to be some amount of dust in the air and always play my records with the dust cover down. Also, I always use my Audioquest Anti-Static Record Brush and Onzow stylus cleaner before & after every play, Mobile Fidelity LP#9 after every listening session and keep my records in Mobile Fidelity inner sleeves. Until I can afford a man cave with clean room protocols, that's the best I can do.