In the morning, I glued up the layers to the second horseshoe set exactly as I did with the first set yesterday.
When I got home in the evening, the glue was dry on both sets, so I was able to route out the hydraulics and button holes. Recall that I originally routed only the top layer to size, and left the others rough-cut. Now I was able to route out all the rest of the layers together, using the top layer as a template, and get a pretty good match.
The results were positive. I still need to apply some wood putty to the seams and sand them down so you won't be able to see the various layers in the holes.