.... But I wince at spending $900 for a cyclone with .5 micron filters -
yet that seems to be the only way to "really" do it. (the jet cannisters
only go down to 2 micron...most bags are 5-30 micron) ...

A long story short --- I had been plagued with a persistent cough for a long
time. I tried several medical approaches. Then it hit me. My basement shop
was full of wood dust, and an old waterlogged drywell would allow water into
the basement. I realized that I was being constantly exposed to mold.

I did two things: I installed a dust collection system, and, also as
importantly, an air cleaner. The air cleaner has a 1500 CFM squirrel cage
fan and four filter stages. I put on my respirator, blew out the shop with
compressed air, shot over pipes and exposed ducts, left the cloudy room for
about 20 minutes, and repeated this several times. My cough stopped soon
after that and has never returned. I've since gotten a second identical
cleaner.

Now, run the air cleaners any time a piece of machinery runs and I blow out
the shop at least once a month.