A 1/4" diameter dowel was picked to even out the epoxy fillets.
It was marked with a wide tip Sharpie pen to transfer the width lines onto the fillet area.
This idea comes from Crazy Jim's tutorial on TRF HERE
I thought I'd have to continually add more marker to the dowel, but one application did the trick for all six root edges.
Gently rub the marked dowel on the body tube and fin and the black lines are transferred. Be careful not to "scar" the balsa.
Masking tape was applied down the faint black lines to control overflow of the the epoxy.
When you use the dowel to even out the epoxy, it will go over the masking tape. I'm using 15 minute epoxy. When the epoxy just starts to set up, just a few minutes, remove the tape. Otherwise - the tape might get glued to the fins.
After pulling the tape, ther'll be a slight epoxy ridge where the tape edge was.
Dip your gloved finger into a small cup of rubbing alcohol. Shake off the excess.
Run your finger down the epoxy fillet. This should knock down the epoxy ridge left after removing the tape.