leaf spring torque
The springs don't actually slide in the manner you think. Since there is a center pin, they cannot slide, per say.
Best way I can describe it is this. Take two yard sticks. Clamp one end tightly with vise grips. Bend the yard sticks. Then remove the vise grips and do it again. You will see the difference.
It's about letting the front and rear segments do their separate jobs. If the plates are over torqued, the suspension will bind. If they are torqued in the air, the suspension will bind.
None of this is a CIA secret. If yall would spend 10 frikkin dollars on the MP suspension manual, you would learn a lot. It's all in the book.