I got my brass template guides yesterday from Pricecutter(including a 1" O.D.). Right away I built a modified version of your dado jig. I modified it because I dont have a 1" bit or 1/2" MDF. So I cut down 2 planks of left over laminate flooring using 1/2" plywood on the ends and the new 1" guide for the spacing. Works great. I,ve allready used it to route a stopped dado in the surface of my new table. So I could add T-track(not miter track) for feather boards or whatever else I may need. Would post pics but I'm having trouble with my camera.