Colored Vellum is fun to work with. The color is already built in, and all you have to do is emboss the design. Most of these papers are on the heavy side, so pace yourself. You have to push pretty hard to make a good, solid white dot. Piercing tends to get lost on colored vellum—there isn't enough contrast.
Any color in the paper will make it harder to see through than the completely translucent vellum; and if the color is at all deep, you won't be able to see the holes in the template underneath. Luckily, transmitted light from below makes the holes easy to see. You can acheive this with a light-box; and for contrast, you need to color the template black with a permanent marker.