I "thunk" to myself, well what do you use to make a dented tube round again?...and a lightbulb went off. Use a muffler tailpipe expander!
I borrowed my buddy's 30 year-old piece of iron hardware and plunked it in the center hole, gave a few whacks with a dead blow hammer and voila! Perfectly round again. It didn't even hurt the inner center cap mounting lip on the cone. It just moved everything back into place.
And here is the result:
