1-
Is there one respirator that insulates do-it-yourself boatowners from
the risks of breathing all the various toxic substances they will
encounter from welding, fiberglass work, paints, solvents, lead, etc. ?

How can comfort be optimized while wearing it ?

2-
If one goes the remote filtered air route, what "mask" is on the market
that is safe, competitively priced, that connects to the air filtering
apparatus ?

It seems it might be more satisfactory in terms of air quality to go the
remote supply/filter route, but there's the hose and then, mask comfort.

Comment ?

Thanks to all for the benefit of your observations and experience,

Courtney