You're probably overthinking it a bit. You just outline your plate on the wood, drill out the center hole, then stick your router in the hole and rebate out the square pattern you drew on the wood. If you looked at my build, I just cut a couple steel strips to length (doesn't need to be exact). I painted mine bright white. Under the metal strips are little pieces of wood which press against the stick plate. Again, it doesn't have to be the exact thickness, because you just have to add thread locker to the threads and then slowly screw down until it feels nice and tight.