A daring attempt to not waste material. I wanted to do this one without needing tags.
It seems to go wrong on the above picture, where the two clamps can't stop the top edge lifting up a bit.The underneath of the arch seems to join perfectly, so the lifting edge went back to where it was when I moved the clamps. I might try clampless machining. If super glue works well enough, it might be worth clamping the Delring to the wood with super glue.