I have been considering having one of my fretted basses converted to fretless. It's a Ken Smith five string with bolt on neck and pau ferro fingerboard. I was considering a fairly traditional conversion, having the frets pulled and slots filled with maple strips, but both a local luthier and Ken Smith dealer suggested I consider having the frets filed down and leaving the tangs in place as position markers. I've had various fretless basses in the past, lined and unlined, but I've never seen or played one with ground down frets. I'll put this question to the luthiers out there. Is there any significant advantage or disadvantage to grinding down the frets instead of pulling them? Has anyone ever done this kind of conversion? If so, how did it turn out? I tried searching this topic and found some speculation but didn't find any really definitive answers. Thanks.