Hotchkis leaf springs sagg brand-new

I think i understand the spring rate issue, but im thinking my current hotchkis springs are more like 90lb/in where they are advertised as being 130lb/in.

I shouldve mentioned the dana 60 is a Strange Dana S60; im not sure what center section they use. I would like to be about where my old, weak slant 6 springs had me height wise. I didnt change the front height between the slant 6 and MP springs; the front is lower than stock despite the headers and oil pan (i think the k-member is ~6" off the ground, i know the oil pan is 3.5-4" off the ground).