I just use the cheapest possible brushes for building up clear. If they lose a bristle or two some fine sanding will take it off.
The real painting is doen with an air brush.
By the way, modern dope can be re-disolved with thinner or acetone. The old stuff (Aero Gloss of the 60's) dried with a chemical change that could not be reversed.
In the old days I could do a multi-color brush job with no problem. With current dope the second color will disolve the first and make new color. Hence the air brush system.