My 82 was 23inches to bottom of frame on 40s. im running bottom 5 springs from a waggy pack and top two are stock toy rears. and chevy out back 2 leafs plus over load. no blocks and a 6inch shackle. If your runner was mine this is what i would do. I would start off by sucking the front hanger up into the frame. ( your hanger has alot of drop in it, Where my skys hanger has alot less drop)your front shackles are already french into the frame so your good there. make your self a ruf pack.( could even use some springs from the tg pack) And out back i would go with the chevys or fords, And french the hanger as needed. Its alot of work to be done. But it will be worth it in the long run.
Im getting ready to do all this to my blazer. witch also started life as a 2wd. I am planing on being under 25 inches to bottom of frame on 40s when im done.
Forgot to add. I would swap out spring first to see how it works then if needed start cutting and moving all your hangers.