From the car's previous owner:
"The rack on your Van Dieman is in a hidden spot and to centre it and lock it in place is tough to do so I made the piece in the pic. When I mentioned that the pic looked off it was because that pointer looks like it is beside the steering column and should be just above the top of the column and there should be a mark on the column, centre punch, scratch or a paint spot. You mount the piece as you have it (if the pointer is too long then I must have used shims but the pointer could be snipped off to length, ie: right above the column) and with your steering centered you find the mark or make another one (ink mark on a piece of tape works) and bend the wire pointer so it sits above your mark, if you move the rack when breaking your lock nuts on the rod ends it will show at the mark/pointer."
So there you have it.