Thanks for the help Sam, You advice is greatly appreciated. I think I'm getting closer to having enough information to at least talk intelligently with the spring manufacturer. With the stock springs having a 304# spring rate in the front and the 1st stage of the rear having a 175# spring rate(adds a 237# spring rate when you get on the 2nd stage overload section) total of 412#. I may be closer than I thought, with just the second stage of the rear being a bit too stiff.
I don't know what happened to Billy, he left me somewhere between leaving it stock and no more than 125# WHEEL rate, which I gather is my SPRING rate.
Again Sam, thanks for taking the time to discuss it. When you mention leaf spring suspension with a straight axle in most circles, people just tell you to whack that crap out with a torch and get IFS, then whack out the rear and get a four link. I just march to the beat of a different drummer, I'm gonna make this old buggy spring truck drive and ride good with the original design. No cutting torch required.