Keep you're fretted bass and pick up a fretless too. Then you can bring both to gigs which keeps things interesting. As for lines? I've never had them. I put a Snark on the headstock at home to help play in tune which is an ongoing challenge. I don't think I could really look at the lines, but I do measure where the 12th and 24th frets would be and draw a pencil line when I set the intonation.