In the back, I found that one of my original leaf packs had a snapped eye in front. So I ended up getting some "stock spec" springs from Stengel Brothers and replaced them. I also put in a full length add-a-leaf kit meant for a Jeep Cherokee XJ. It was advertised as a 2" lift kit, and I got it from Iron Rock Offroad though I think others are available and are similar. Finally, the bolts on my rear shackles snapped when I removed them so I had to use shackles from a Jeep CJ7. The stock Eagle shackles are 3-1/2" long and the Jeep version I used was only 3" - so this lost me about 1/4" of height in the rear since they say you adjust by half the length.
Once I was all done, I measured front and rear at the sill and it was pretty level. Within 1/4" front to back, with the rear just a hair low. If I had stock shackles I would be dead level. Frankly, it's not really noticeable and is probably due to my disappointment with the short rear shackles. I may try finding some 4" shackles which should raise me another 1/2" in the back, and go for the "I just bought air shocks for my 1976 Camaro" look.
So, if you have stock rear springs with useable Eagle shackles I would highly recommend a full length 2" add-a-leaf kit. Get new U-bolts too while you are at it.
For the shocks, i used Eagle spec both front and back. I used some short extensions in the back, they were needed. I didn't need shock extensions in the front at all, since the difference in ride height where they attach was much less than the 2" (geoometry!). My front shocks are serving as bump stops, they are the limiting factor for how far down the arms can droop. That seems to be what the factory intended, and at full droop there is about 1/2" between the frame rail and the bottom side of the upper arms. I didn't measure or take pics of the control arm gap before the swap, but I believe the change was minimal there - again because of the geometry. It was certainly much less than 1" change at the sill, since it is so far inboard.