I have an SX J that has a maple fretboard. I want to make it a fretless and have a few questions. 1) If I'm planning on using flatwounds do I need more of a fretboard coating than it already there on the maple fretboard? 2) What should I use to fill the fret slots? I think I want to go with a lined fretless fretboard, but I don't think I want black lines. Thanks!