I was planning on making templates as well, tape them up to find the best fit, and then use a hole punch to create my marks in the templates. Finally, transfer that to both the vest and armor plates. In theory, it sounds right, but I figured it might be a two person job to get it perfect.
Also, instead of the epoxy, I was planning on using Quick Plastic so I could just mold the putty around each bolt by hand.
Looking forward to the pics!