[wingnut60]

One thing to keep in mind about the softer bolts--the tubing is much harder than the bolt, and the edges of the tube constantly rub against the bolt. I would suspect that this wear is more of the problem than resistance to movement causing the failure. Sure, if there is a real bind in the movement, a harder bolt may cause more damage if it doesn't shear. In my case, the gear pack bushings wore out causing the shaft to be out of line and the bolt sheared--not sure if a harder bolt would have caused more damage or not.
With one instance in 7 years of use, I think the softer bolts are in order...