First, I made a bunch of 1-3/4″ x 6″ pieces of 3/8″ UHMW. Then I setup a guide on the table saw to cut all the corners off.
I made a template for the cleats out of plywood and aluminum diamond plate, which I then used to cut the other area out with the router (flush bit). This yields a nice cleat, with pre-marked holes (where I will countersink a screw to attach them to the treads).
This isn’t the fastest process, so it will be a few days before all the cleats are finished, and then a few days to attach them all.