I found I had to get my leaf springs completely flat straight with no arch to get the ride height I wanted for my datsun 1000s. You might be better off with sports options on the tension and going flat straight with a minimum curve that way it wont be bottoming out however can also use weld on suv chassis cavity pockets to increase clearance once lowered to avoid any bottoming out. You would be able to use adjustable dual acting Konis or similar coil-overs to adjust firmness further as the leaf spring being flatter will have more flex.

I used 1989 nissan navara front oil shock absorbers for the rear they are short and cheap improving the overall ride substantially with very predictable steering once the rear is hardened.