The 2" faceplate ring does indeed screw into the block. It is my experience that this ring is more accurate than any faceplate I have so far. I have no run out when I flip the block and the only time that I do is when the cut on the bottom is not clean.
The screws I use is a #8 woodworking screws with double threads, #2 square bit heads and very high quality.
Amazon.com: The Hillman Group 5937 Pro Crafter 8 by 1-Inch Wood Screw, 50-Piece: Home Improvement This is the exact screws, I found them at lowes and have been super happy ever since. I found that the regular POS screws that I was using tends to slip and eat out the wood quite often to.
I have 2 types of respirators. a P100 and N95. I used the N95 on this project the whole time. It is one of those cloth with 2 elastic bands and the metal clip over your nose. The P100 filters out all smell like from chemicals, pollen, lead, asbestos, mold, etc.. If you are in some heavy stuff the P100 is the bomb. The N95 is mechanical only, which means dust. Either will be workable for asthma, allergy, breathing issues.
As for skin goes I just turned in a t-shirt and shorts. Since it's mid 80's here and 60's at night (right outside Columbus GA) and I don't have a smock I got pretty messy from this. A good smock would keep all dust/chips/dirt/etc.. from your body/clothing/skin. So far the best design I have seen is from Lee Valley.
Lee Valley Turner's Smock - Lee Valley Tools With this the only possible contact would be face and hands. A face shield and Nitrile gloves would fix that right up. Also a good shop vac/dust collector that's on close to 100% of the time. Right now the bowl weight is 1 pound 15 ounces. When It was round and with the faceplate on it was 9.6 pounds. So there's about 8 pounds of dust/shavings to deal with.
The WORST part of the job is sanding. I was super careful and had minimal tear-out but did have a few deep spots which took some sanding to bring them out. I always run the shop vac with a 4" square magnetic attachment while sanding, it's quite fun to see billions and billions of dust particles flowing off the spinning bowl and into the vac and no it's not a straight line either.