Which leaf springs to use?

No easy to modify the rear segment as the
metal is hard as Hell.
But you could easily modify the rear spring hanger
to move them up .75.
Male sure shackles are leaning BACK and not forward
when you are done
Plus be prepared to reroll you front fender if the tires are ;arge
diameter.
I routinely move up the rear end .75 forward.
Sometimes the K member as well.
Think you missed a key part of my question…. I burned in (welded) sliders too far forward by .75”. If there isn’t an easy fix like a custom set of rear section splits, then I will have to cut off the sliders and re-weld further back.