I repaired my Willis strap by punching another hole above the last factory hole with the correct sized leather punch, then used the little leather plug from there to fill in the home made one. I used the punch to correct the homemade one so that the plug fit exactly, and secured it with leather glue. As you can see in the photo, it was in a super weird spot, off center and barely above a factory hole.
View attachment 3841563 You can barely see the repair in real life-I took this photo under two Ott lights. My leather punch is open behind the cutter tube thingies, so it was easy to just push the leather plug out with a toothpick.
Hope this helps!