Nutty,
you are not wrong but we all know he knew what he meant.
I sit in amazement over how many column inches have been generated over a simple nut and bolt. (I was reluctant to join in to begin with)
the problem I have seen with shoulder bolts is that the thread gets undercut making them liable to sheer off if over tightened.
May be better to use a spacer tube. but I have not studied the assembly and constraints.
Let us hope what ever happens they get the books clear so there can be no scope for variation. In the Auto industry we used the term Poke Yoke to describe things being fool proof. I did a course at the Smallpeice Trust at Warwick a while back.
Drag