Hi Philip. Thanks for the friending.. i’ve Made fret markings in many ways. Wood burning can work good. I just got a great CBG from Vern Hallet with burned markings. He notched the fret positions first in about 1/16 wide, then burned in the groove. It’s a hard Maple neck.

i like to spray paint the markings. I mask off the board leaving spaces at the marks. About 1/16. Then spray lightly with Rustoleum in a color that contrasts the fretboard. I sometimes use two colors for a gradient line. Like white and red. I usually stripe my fretboards. I mask off the board leaving 1,3,5,7,9,11 etc. open and color the openings with a color that relates to my box and makes a good background for the MOP dots.

as far as springs go, i’ve Not tryed that yet. Others have had some success. I think they might rattle if they touch the box wood like a snare drum. I like a clean sound so I avoid rattles. Your Boneshaker might like a rattle. I bet it has good sustain. Keep on makin those cool guits Philip..