Two years after the start of this thread, here is the tool in action. I made it before I took the axle out to confirm it was correct. Of course the axle could have been somewhat out because of bushing and bearing wear. Anyway, with the new axle in, it worked like a charm.
During this process, I discovered (correct me if I am wrong) that the tool isn't totally necesary. Here is my argument:
The center arm is fixed on the top side by a mount on the trunk pan which means it can't move side to side. The lower half is secured by the cross shaft adjustment. It's purpose is the move the lower arm side to side which in effect causes the center arm to tilt (see pic). I discovered the center arm and therefore pivot bolt (with the dimple) is in alignment when the arm is square to the body (staight up and down). This can be determined by the large washer on the mount in the trunk which is square to the center arm when snug. When the large washer is level (or parallel) to the body, the arm is square and aligned. Easy to determine by a common spirit level.
Initially the large washer was not level until I used the alignment tool at which time it became perfectly level.
What do you think?
