FWIW, My Mustang had the inverted snubber setup you are thinking of. Probably cheaper than Cal Tracs or new springs.

One other thing to consider is clamping the leafs on the front half of the spring together. YOu can clamp as many as you need to stffen the front segment and control spring wrap up, assuming you don't need more than all the leafs clamped to control it. That's old school but it works to an extent.