I have no clue....if I were you and looking for answers on how to make a ford handle I'd be reaching out to Mike Maier. Mike Maier Inc just came out with a new spring pack for mustangs, he's got a ton of knowledge on making cars handle on leaf springs.
The other guy is Ron Sutton. He's recently taken another ford and put it on composite springs with a locator and JRI shocks, he's transformed the entire feel of the car.
There is a science to springs and getting them to work as designed. If you add a panhard or watts link you are now allowing the spring to travel up and down as designed without the lateral load. That lateral load messes with the travel, spring rate and causes binding, not what the spring is supposed to be doing.
Hopefully Ron or someone with more knowledge chimes in. What I do know and have seen is you don't need fancy shmancy 3-4 link set ups to be fast.
YB still around?
