I have to agree with Paul McGaha in post 13 and Glenn Bradley in post 34 and Ben Rivel in post 45- your health is worth the money spent on GOOD DC. Ironically, one of the early "any old thing will suffice" posts was from Kent Bathhurst, who used to frequent this forum and whom I miss, was both knowledgeable and then cantankerous -- - - last picture I saw of him was in another member's shop wearing an oxygen mask and pulling a green tank around. I assume his opinion might be different today . . .
Also, many people refer to the information on Bill Pentz's site, which is good, but seem to miss (or not emphasize) the reason he posted all of that information - - - his experience should make believers out of all of us.
Stay safe, breathe well, patrick