Actually, I have been doing this for over 2 yrs. Use only a black Sharpie! Both red & green will run if they get water splashed on them. I have a 5' x 9' padded table that I gridded with 1" squares over twenty years ago. I have metal ruler strips on both sides, so it was fairly easy to grid.
I did use both red & green on the long edges at 2", 4" for pressing up hem lines for draperies. The red & green only run if they get wet. They can be steamed.
You can press any angle on the one line, because you just line up the stitch line. It makes a lot of difference.