Well, here is my approach to plugging the four 3/16" holes. The holes in the shell are super clean so I do not want to attempt to make them bigger. So I used 5/16" wood plugs with circles of wrap that were cut with a 1/4" hollow chisel chucked up into the drill press, thank you Glen for that brilliant idea!
Now, I have glued the tiny wrap circles to the wood plugs with good ole wood glue, Tight-bond 2 to be specific. After several hours of drying I will drill a small hole in the bottom of them so they can be screwed onto a shaft that came with my Dremel tool. Now I can turn them down to fit the holes in my shell to perfection. I will have a slight taper to them, and the best part is the wrap circle is now absolutely perfectly flush with the plug.
Now, I have not succeeded yet as the plugs are drying right now. But I did do a test run, one plug that had the wrap dry for one hour or so, it worked very good, I just sanded it too much and it fell through the hole. When I do it for real I will take the drum out to the shop so I can fit them as I go.
More later.