Cutting coils is a bad idea. The top and bottom "coil" is flat (or similar shape) so that it sits in the coil bucket correctly. If you cut that off, it wont sit in the bucket correctly, and if you try heating it to reshape it the springs temper is destroyed.
The limiting strap idea would probably work, at least until those straps break from being under constant stress. What are you going to do when 1 breaks while you're driving it?
Buy the right springs, whether that means new or finding some used.