Surely a dowel with screws or rivets will secure the piece. Consider tube cutters when cutting the tail... I am a plumber and we have tube cutters that with patience should cut the steel, usually used for copper though I have personally cut stainless tubing with them, may mark the paint though
, reco test run first.They will ensure a straight cut so when you re join it the two pieces should marry together nicely, certainly better than grinder/dremel cuts. Pick up a decent pair at your local plumbing supplies for around $50.00 or alternatively make friends with a plumber.
Good luck.