I like overlays, this one has a stringing groove added so I can use my parachute cord stringer on the bow.
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Instead of flattening the back of your bow, cut the shelf for the overlay at an angle toward the belly. This way you will have a graceful overlay instead of a big hump on the back of your bow.
I replace an overlay on a finished bow occasionally. The overlay in the picture is a replacement, you can see the a little bit of the overlay that broke under the new overlay.
I did another replacement last week after I dropped a bow that hit on its tip on a concrete floor and cracked the overlay.