Make sure your springs are in good shape and are not cracked or have a dip & ridge wore where the shorter leafs end on the longer ones.

Depending on how many leafs you have, you can remove as many as every other leaf, but that will probably make it pretty soft. The last one I did, I kept the two longest leafs, then as they get shorter, removed the 3rd leaf, then the 5th leaf, and then the shortest one (if you still have 2 left). The shortest leafs are the strongest, but they also put the most load on the main leaf. I prefer to pull the shorter leafs first. Keep in mind the original springs are more narrow then modern leaf springs, and they will weaken faster.

Moving the axle from under the spring to above the springs will lower the truck the thickness of the spring pack plus the diameter of the axle housing, could add up to 6"-8", will probably require new spring plates and shock plates, and may require notching the frame.

There is enough variation in the old trucks that changing the leaf spring leaf count gives inconsistent results. It really will be a trial and error experience. Gene