Someone might disagree with me and provide better info so I'd wait for others to chime in, BUT..
I'd cut the bottom. If you look
LOL beat me to it, because I left my message unfinished in the edit box. These last few days really got away from me..
"If you look"...at the bottom of your existing spring, you'll see where it pokes into a curved slot in the lower control arm. When you cut at the bottom it's easy to replicate this. The top of the spring is cut flat...which you may have a bit of trouble doing.
Richard