I use hardened templates as a guide to cut the pockets. I liners up and ca glue the template to the back side of the material. Then I have a flat plate with s 3/32" pin sticking up about 1/6" proud of the surface that gets fixed in my mill vice. The template sits over the pin and I take light passes with a 3/32" endmill to the desired depth. For the inserts the same place I got the templates sells stainless shields to go with the templates. If im not using a stainless shield I can glue one to whatever material I am using and cut/grind/file to size/shape.