Additional observations.
A common thread after installation of the Alcan springs and spring shackles, (with the Alcan non shoulder bolts), is a really rough ride for the first few hundred miles. If you really think about that, it can easily be due to the pinching of the spring ends to the shackles and the shackles to the easy flex arms. Those items MUST break free before the ez flex can do it's job. Those first few bumps must be epic in their effect on the items in the trailer! No matter how well greased those bolts and bushings are, the pinch on the axle ends and ez flex arms has to be overcome before the suspension can even begin do it's job. I do not even want to think about the long term wear effect.