I have used Koverall on serveral projects including a Gee Bee that has been repaired several times.
Lately I've had good results using waterbase polycrilic to fill the weave. (First apply wood sealer to keep the water from warping the frame.).
About four coats and then a coat of automotive sandable primer to fill the weave completely.
A light sanding and then painted with Rustoleum enamel paint. Gives a good gloss finish and seams to stay flexable of open bays.
Most of my planes are gas but Rustoleum is supposed to be good for up to 15% nitro glo.