A tight radius bender from RIDGID and then modify it so that you can start the bend soon after the nut and collar.
I have an Imperial/Eastman tube flare kit (aircraft) that roll's the flare into the material and the when it backs off it burneses the material. You cannot compress the flare into the material because it work hardens and splits most of the time. That bender is around $300, There are other benders out the that people say work, never used any of them to give an opinion on how well