Assuming I have successfully removed the frets from my bass fretboard, what should I fill the grooves with? Should I remove all of the frets then fill the grooves, or should I remove a fret and then immediately fill that groove. Once I have filled the grooves how should I sand the fretboard down again? Have any of you applied epoxy or anything else to your fretless fretboard, and how did you do so? Thanks!