The original plan was to use the texture on the front and cut a wavy edge. It just did not seem quite right after laying the pieces out together, so on to another design idea. With the roller printed side down on a bench block covered with a thick piece of plastic, such as from the lid of frozen whipped cream substitute, lightly texture the smooth side with a favorite texture hammer. The plastic will help save the roller printed texture.
Form 14 gauge round wire into an 8mm ID ring. Hint: One step down from the largest barrel on a 6 step barrel pliers will make rings of this size. If Argentium wire is used, the seam can be fused. If not, use hard solder to close the seam.
Place the ring in the position desired on the back of the half circle. Use an ultra fine point Sharpie to mark on the half circle on either side of the ring. With the front side down on a bench block covered with a thick piece of plastic, stamp the metal content, in this case .925, between the lines.