Sounds like a combination of them two methods could work. Nail overcoat (varnish?) With glow in the dark powder in it?~ i love whittling and SAK's ~
Combining a couple of ideas here... there IS glow in the dark nail polish.Pain it in, let it settle in the crevasses, wipe off the excess, wipe down tool with nail polish remover to get rid of remnants, but lightly, so as not to remove it from the ruler lines. That might work.