My next build is going to be fretless so I was wondering the same thing , I'm sure were got lots of suggestions .
My first build is fretless. I put markers and dots along the top edge of the neck and at the very bottom edge of the fretboard. The marks and dots at the top help. Can't see the small marks at the bottom of the fretboard when playing. Going to sand the marks on the fretboard off before I put a finish on.
Lots of ways to do it. Your ideas are good. Don't forget marking the side of the neck too. A difference between fretted and fretlless is that side markers ( usually on 3,5,7,9,12,etc) are between the fret and the prior fret ( between 2/3) on fretted instrements and are on the mark on fretless instruments.
This is about where you place finger or slide on respective instruments.
Build and play...Have fun!!
I use a small round tip on my electric wood burner to make the fret board and side markers. Light sanding and then a few coats of clear spray on acrylic.
On my fretless I use plastic knitting needles as markers/wood dowels for the side of the neck...
On fretless I only mark the side of the neck - I use 1/4" or a bit larger for 3, 5 , 7, 10 and 12 and smaller for the others - I drill a swallow hole and fill it with contrasting wood filler - I sometimes use a wood sealer first so it doesn't sit in the pores around the holes.
No - I've tried dowels, but couldn't get the contrast I wanted. Someone earlier mentioned using that clay type stuff you can bake in the oven to harden - you can get lots of colours - one day when I'm in Micheals or where ever I might pick some up to give it a try. I was even going to try the bigger plastic coat hanger material. Just haven't got past the wood filler yet.
I've used those Sasquatch. Plenty of UK eBay sellers of those too. They're pretty simple to use.
I've just used them on my first build. Easy to put on and really pleased with how they look. This is a fretless build so used one dot for each fret but think I might have been better off using different colour / size for frets 3,5,7,9,12 etc.
Bought 5x20cm rods from Touchstone Tonewoods for £2.20 and just worked out that will be enough for about 25 necks!!