An electrostatic rotary atomizer (a standard piece of industrial equipment) has a log bimodal droplet size distribution, the product of which is very easily air classified. Cab-O-Sil is a VERY common ingredient in numerous pharmaceutical products. It produces a thixotropic mixture that is well suited for rotary atomization into single-digit micron sized droplets that shrink as they dry.
Any industrial paint or drug formulator knows this stuff.
I don't see making the powder to be as much of a challenge as would be containing it so that it didn't kill me.