Good thing you're getting that squared away ep. I've seen quite a few add-a-leaf kits installed that way. I know how people think sometimes, but not sure what logic they use to try to squeeze that thick overload leaf into an arc, and why they don't notice that it's not doing the job the minute they start to put it together that way.
Add-a-leaves are a perfectly viable option. Maybe not "the best", but certainly not "the worst" either. Everything in it's place.
Hopefully the time they spent smashed up against the overloads didn't clap out the add-a-leaves though. They may be ok, but don't be too surprised if you don't get the full amount of lift you expect.
Crossing fingers at this end anyway.
The longer the leaf, the better riding for the amount of lift. But even short ones can improve the performance and feel of a clapped out original spring pack.
When spring packs wear, they often take a set and wear into the adjacent leaf. This gives the lower leaf a notch to get locked into and takes a bit of push just to get them to slide out of the notch.
When that happens, they ride like crap. When you add a leaf that changes the arch of the pack, and therefore the position of each leaf end, you can actually improve the overall ride feel by reducing or eliminating the extra force it used to take to get the springs to slide on each other.
Sure, it's "stiffer" (because you added a leaf and more spring-rate), but it might actually work out to be less "harsh" in the ride department.
Seen it happen often enough.
Maybe you'll get lucky and your wife will actually like the new road-manners. Lots of attaboy-points built into that project!
Good luck.
Paul
