I use Rust Oleum Painter's Touch Latex paint for the letters. Spray paint was too thin and wicked up the grain even on some that I had put sanding sealer over first.
Since the letters are V carved with a V60 degree bit there is lots of room for paint. I slobber it on and keep cleaning out the letters. After it is dry I hit it with 120 grit then stain 3 times. Using LP air to blow the stain out the letters and the carvings while wearing a respirator.
Thanks for asking.
AL