have you looked into using project curve onto your surface, then use divide face, then select these faces, and color them. When you project curve you have options, along vector, normal to surface. I would try along vector first.
What is the overall purpose of this ? A 3D warning sign, where different colors appear depending on the "thickness" ??? another trick could be placing the text , say 0.1 mm above the plate, then extrude the text, distance = 0 - will create Sheet bodies. Regards, Tomas