The primary purpose of the wedge is to be used to straighten cylinder yokes that are sprung.

If the cylinder is sprung upward, the wedge is pushed in between the frame and the closed cylinder, then tapped to bend the yoke.

I strongly suspect that if you try to bend the spring in the frame, what will happen is that you'll break the "fingers" on the spring or break the hammer stirrup the spring connects to before you get a bend in the spring.

These days with so many after market springs available, it's not really necessary to bend springs.
Instead you can install a after market spring and tune the spring tension screw to get whatever you want.