I’m a little dense, so I’m still trying to get my head fully wrapped around this procedure.
In the attached picture, I have the “official” BRP alignment screw (as noted in a similar illustration several times previously) inserted through a hole in a piece on the side of the steering column, then screwed into a threaded hole directly below it in the aluminum Pitman arm support. It’s the only place it (or the countersink headed bolt) can go if the steering is straight and the two holes are aligned with each other. The fancy BRP spacer with the long-slotted hole is omitted for clarity.
If the above is correct and the whole point of this procedure is to just lock the steering in place so it won’t move, then that long slotted hole in the BRP spacer is useless in this application. The same thing could be accomplished with a stack of washers or machining a slug of metal with a hole through it for the screw/bolt to pass.
I appreciate the help, I really do, but just sticking up a confusing picture with no accompanying dialogue can raise more questions than sensible answers. It certainly did in this instance, for me anyway.