56" rear springs 1970 4x4

[gunslinger]

Wondering if anyone has upgraded to 56" rear leaf springs on a 1967-1972 C20 pickup. I would like to do a 6" lift using the ORD shackle flip. They offer it in a 4" lift according to the web site. I cant find 56" EZ ride springs with two inches of additional lift built in. Tuff Country list 4" and 6" from what I have found. If anyone has done it, what did you use as far as flip length, springs, shackle length? What other areas need to be addressed as far as axle centering, geometry? Not to be disrespectfull, but I called ORD and a female answered the phone who might not have fully understood my questions although she was very nice. Any help would be appreciated. Looking for flexability and load carrying capacity similar to what Dirty Larry did to his rig.