I took a bit of a chance.
After looking into the different add a leafs ( Summit sells like 3 or 4 kinds ) I ended up
Pro-Comp's Full size truck/van/SUV short leafs.
I came to this conclusion on a couple of matters.
I kept digging on Summit's web site 1st for the extra lift the springs advertised.
Then I began to further narrow by picking the same spring width.(some were 2, 23 or 2.5 off the top of my head)
After much thought, knowing that my old springs were sagging a bit, and knowing that I didn't have a couple hundred to drop on new springs right now, I settled on Summit's P/N EXP-13122.
After dropping the old springs ( 1 side at a time ) I c-clamped the pack together, cut the old spring pack bolt out, took out my smallest "mini" leaf on the very bottom, moved the next spring to the bottom below my add-a-leaf, c-clamped the pack back together and re-bolted them together using the supplied new bolt.
Like an idiot, I didn't measure any fixed point off the car to compare how much lift I ended up with, but it was somewhere in the neighborhood of 1-1/2.
I have been measuring to keep on eye on how much relaxing the spring will do, and so far not much.
For as well as this worked, and someone correct me if I'm wrong, but I was surprised not only to not find anything on the old world wide web about anyone adding a set to car instead of a truck, but that no one seems to advertise anything for a car.
Hope that helps Geneo4116!