You might try a razor saw. They're a little more controllable for small jobs like this.
Might be easier than a hobby knife. I'll still need some kind of cutting guide tho. Can't easily wrap paper around the tube because of
the pylon and impossible to get an Estes tube cutting guide onto there. I'll rummage thru my spare parts bin to see what I can
come up with. Thanks for the suggestion Steve.
Only other fix would be to carefully smooth out all the crinkles (use the nose shoulder as a mandrel as needed) and then soak with CA. When dry, sand smooth. If you need a bit of filler in the process, baking soda works well with CA.
That sounds the least destructive and risky, glad I hadn't started on the fix yet. Worst case if it doesn't do the job is I'll have to fall back to hacking off the damage. Thanks for that tip on baking soda and CA btw.