I know Ziplock bags work and I was reading those speculating Styrofoam also might work. Then someone commented "put up or shut up" - paraphrased.
OK Challenge accepted!
My wife gets these mailing coolers for injection medications:
Dumped some Lee 401-175-TC's
White BB's
HF Red Powder Coat Powder
Swirled for a minute or so. NO SHAKING AND NO LID NEEDED
Most boolits were 90-99% Covered, some a little less
Twirled them with the powder dusted glove, about 1/6 turn each time
Ready to bake, I left a few on the left with open spots
Done Baking
Notice that the paint spread over the empty spots on the boollets in the left front rows.
Here's a video of how I spread the powder over the boolits with my gloved hand