This is another case where I am very glad to have invested in the CNC router and the time to learn how to use it well. It makes the creation of precision wooden tools relatively easy. There is a certain complexity to it, though. To carve on an existing piece, I needed to create a point that I could locate exactly in the computer. I chose a point 1/2" down from the center of the paper recess.
Once the slots were cut, I grabbed some pieces left over from cutting down plates and sized them for the rail slots. They are exactly the same height and composition as the plates and the slots are cut exactly as deep as the recess that holds the plate.
Rail height, just enough to consistently receive the pressure.
The results are beautiful. The pressure looks consistent, even on the new, complex plate with no borders.
In this image, you can also see that I am designing the geometry plates to be used together for varied and interesting effects. I'm designing and carving two or three new block designs each week so soon I'll have a large palette of shapes to choose from while I continue to experiment with color techniques.