When you compare brand new aftermarket parts to fatigued oem parts its hard to gauge whether you are getting actual lift from the new parts or whether the difference is only from how much the springs have sagged and how fatigued to torsion bars are. If the truck has been used fairly hard off road the torsion bars will actually twist permanently and you will lose height and spring-rate. using shocks for valved for suzuki samurai could result in to light of dampening and may lead to a harsh ride. BTW all of the control arm hardware and leaf spring/ shackle should be tightened on the ground under the full weight of the vehicle. Otherwise the bushing will be in essence preloaded against compression travel.
As an additional side-note: Cranking the torsion bars does *not* Increase the spring rate.
The only thing it does is add preload which can raise the height of the vehicle which increases the vehicle's scrub radius (the distance the tire has to move to the outside of the vehicle during compression) which also makes susp. compression difficult. It also facilitates increased upper ball joint wear.