Let the black on the solid surfaces dry good and hard ( thick dope can take days to fully dry). spend 10 minutes with sone 100 grit, the 10 more with some 220 to smooth out the streaks and brush marks. Thin the rest of the dope out a bit so it will flow nicely, and get a fine bristled good quality brush, maybe $3-5 at Home depot.
A couple light coats will finish it off, and a bit of rubbing when fully cured will surprise ya.