I like overlays, this one has a stringing groove added so I can use my parachute cord stringer on the bow.
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.