I think I may have figured out your problem. The curl on the spring lays on the round part of the finger. The other end doesn't hook on to anything. I just took one apart from a 1956 and if I hook the spring on the lever like you show in your picture, it makes the lever turn. The spring is there to provide up and down tension between the finger and the 2,3 lever but not to put twisting tension on it. Try assembling it with the curl laying on the back side of the finger and don't hook the other end to anything.
