Just some thoughts for you when you're clamping drum shells:

You can use pieces of wood running the length of your drum shell - one outside and another inside the shell. If the wood has a very slight concave attitude this will help put pressure on the shell when you clamp it (kind of like a spring). But it can be just two straight pieces of wood - it will work fine.

I used this method to clamp & reglue wrap on some drums. I know your task is different but the method should work in your case as well.

The above method is just a handy way to clamp if you don't have clamps that will span the length of your drum shell.

For something that bad you should make sure that the shell does not go out of round when you are clamping it, once the glue dries it will retain that shape.

...and to do that, I've used turnbuckles to span the inside the shell, exerting pressure where needed to coax the drum into round. Sort of like the attached picture, but don't forget to use some scrap wood as a cushion at either end of the turnbuckle so you don't dent the inside of your shell.

Thanks for the help guys, got her fixed up and back in action Cool1