The point is not to make it ride as high with a heavy load as it does when its empty.....but more to keep it "level" and not looking like the chest of a middle age hippie at Woodstock.

 

I maintain the same ride height in order to retain spring travel. My coils are 2.5" longer and minipaks and airbags in the rear level everything out. Unfortunately,no overloads on my 2500.
My friend's '05 3500 has the overloads and he fabricated 2" blocks for the spring ends to enable the overloads to contact sooner.
The overloads on my '98.5 2500 with tow package didn't even begin to contact until loaded with 3K#. By then you were riding on the bumpstops.