Sable usually has a black color to it & red has a reddish tint. The red's are a bit finer than blacks. I, personally, prefer watercolor brushes to oil/acrylic brushes for most work. I'll use stiffer acrylic types for weathering, but for detail & general painting I use red sable watercolor.
I have 5-0, 3-0, 0 rounds for detail work, a couple of #3 fans, a #3 round and a few various size flats up to 1/4", but I've been collecting brushes for over 40 years. Most good brushes will be between $6 & $20, just depending on size & function.
OK - your fixed link worked. I would not use any nylon bristle brush for anything but glue application, or house painting.
Reid