Brian.
Glad that you like the Airace mask, I think they are probably as good as you can get.
Look forward to seeing images of your workshop air filtration unit. I did build one using a commercial size Vent-Axia fan which I picked up many years ago from a site that was being demolished, the filter elements I used were large car carburettor air intake type.
Worked well until the fan, gave up the will to live, it was old. I then purchased a Jet unit, that really does clear the air, great satisfaction seeing all of the dust collected on the face of the filter instead of me snorting it. :shock:
Take care.
Chris R.