I have used a hole saw to cut a plug from a spare shell or thin plywood and with glue and wood filler patched the hole.

How thick is the shell ?

I have also used thin sheets of plywood to fill larger holes (about an inch long). You can also find larger diameter dowels at home depot. I believe I have one that is over an inch in diameter and as long as a broomstick. If you can find a round file that is thick enough, or some other tool, you can try to smooth out your large diameter holes to accept the oversized dowel or plywood.

I have a 1960s Gretsch bass drum that had a large hole from where a previous owner installed a Ludwig double tom mount. I sent it to Jack Lawton, who did an amazing job plugging the hole using a section of a 60s Gretsch shell and matching the Champagne sparkle wrap to boot. It turned out very well, and I'd definitely recommend Jack should you care to got that route.

[COLOR="Green"]Having a few junk shells on hand is the way to go. I use a junker 20" for bass drums...works well for 18" and 22" bass drums, too. Then I also have a junker 14 and a junker 12"...which also work fine for the in-between sizes because you are patching w/ wood fiiler and sanding down.

I use old 6-ply beat-up MIJ shells for this because you can actually 'peel' off some layers of ply if you need to make the patch thinner....[/COLOR]

You can cut a piece of dowel rod ,or broom stick i guess, screw a long screw into the dowel, cut the head off of the screw, chuck it up in a drill, get some course sandpaper and hold the dowel with the sand paper and spin it while sanding it to a taper that will fit the hole. then dab epoxy on the dowel and tap it into the hole till it fits real snug, then cut the excess off and sand it even with the shell inside and out of the shell, but this is hazerdous to scratching your finish. You can cut the plug off the right thickness also. If you go with the shell patch method, you could rob a piece of wrap from under a lug, but dont forget to allow for the thickness of the wrap when you make your patch.