Is it really as easy as jackup by way of the body so the rear stays on the ground, yank out the old springs, put in new, drop body down?
Thats all I did, but I jacked it up high enough for the wheels to leave the ground just slightly. Easy as pie.
Also pull the lower end of your shocks. With my Skylark I had to jack up one side of the rear into the wheel well to drop the other side enough to get the spring out. Whole operation including putting away tool time was about 30 minutes.