you can make a tool to remove coil set out of rubber casters. To groove the wheels put a caster wheel on a bolt and nut, tighten the nut down snug, then chuck in a drill and use a course round file to make a groove.
Another way is to clamp both ends of the tubing , then anchor one end to a fixed object, fasten the other end to a come-along hooked to another fixed object. Put some tension on the tubing with the come-along. Go slowly and check your progress, just enough is enough.