I used 89 cent +- "chip" brushes - 1/2 to 3 inches wide--(bristles cut down about 50%) from the local craft store on almost all my CS 17 #307 build (and many acid/plumbers brushes) with quite satisfactory results. BUT, it requires "grooming" them for 10-15 minutes each brush before use. Most new brushes need grooming to pull out loose bristles and particles and particularly so cheap brushes. "Grooming" is using thumb & forefinger to pull the bristles and fanning them against 4 fingers rapidly for particles/dust. Without grooming I got a bristle every 18 inches or so in the epoxy or varnish and after grooming, maybe only 3 bristles in 17 ft., which can be easily "flicked" from the surface with the tip of the brush. I don't re-use them, except for the 2nd & 3rd coats applied just after the prior epoxy coat "tacks" up (non-blushing MAS epoxy is my favorite). All my cleanup is with denatured alcohol--harsher chemicals do bodily harm to me. Even varnishing with "chip" brushes (full bristles--not cut down) comes out very well when I use Epifanes (no-sand between coats) Woodfinish Gloss, over epoxy but I've been varninshing for my whole life, it seems.