The Wegner chair has a pillow rail that fits into a channel at the top of each of the uprights.  The rail slides through a head pillow sleeve, and provides two height settings depending on the orientation of the rail.
 
To channel routing required one last jig (I think I'm up to 13 jigs for this chair).

I used a core box bit to route the channel.

The pillow rail is 3/4" x 3/4" rounded-over on the router table, leaving the ends square where blocks will be attached.

The wing blocks are glued and left to dry.  After that, the top edge was rounded on the router table, and the remainder of the shaping done with a combination of rasp and sand paper.

It was a beautiful day, so I did the final fitting of the rail outside. 

Rail in the high position:

Low position:

 
Arms are next and the last piece of the puzzle.