I got mine, which were modified originals, from Herb. I don't know if Atomic Dog's are different or not. I just put the hinges on the pins, slid the spring on, and then hooked the end on the pin using a pair channel lock pliars. You want the minimum amount of preload or tension possible. A couple of spot welds on the center stud will keep it from sliding off.
I took my springs completely off. I just put the springs in a vise to keep tension on it. Then I popped it off the pin and slowly opened the vise. After that I just used a hammer and chisel to pull it off the post.