Sorry if you've heard and answered this B4, but I'm new to this site. I recently converted a MIJ Fender Jazz to fretless, and really like the results so far. I used lemon oil on the fretboard after filling and sanding the fret slots, but I have heard that some type of finish may make the board last longer so the strings don't damage the surface. (I like roundwounds) Any suggestions? Thanks!