While the edges of the backrest parts were still square, I cut the mortises for the dominos.  Ganging the rails together made a self-supporting structure to cut the mortises in the ends.  The stiles received the mating mortises.

I will be using Danish cord to weave the seat and backrest.  Wegner said, "A chair is to have no backside. It should be beautiful from all sides and angles."  Towards that end, I'll be weaving the backrest like Wegner's CH25 chair, where both the front and back are woven.   Wegner (or Carl Hansen, who built the chairs) designed a clever way to conceal knotted joins of lengths of cord.  The knots are hidden behind a decorative bundle of 8 cords that are woven in a different pattern than the rest of the chair.   Here's my rendition of the CH-27 that I wove in that way using paracord.  The secret to creating that 8 cord bundle only on the back side is by creating a weaving slot that is on the top and bottom rail of the backrest.  (You can just see the weaving slot on the top rail in the photo below.)   The slot provides an alternative path for the cord so that the front and back can be woven differently.

To cut the slot, I made the jig below to hold the rail in position and provide a routing template for a 5/8" bushing.  Obviously constructed from scraps I could grab within reach, it has a plywood base, treated lumber positioning blocks, and a hickory end stop.  Dr. Frankenstein would approve.

The 5/16" bit I have is quite long and tends to chirp, jump and chatter, resulting in a less-than-smooth slot.  Fortunately, the edges of the slot will all be concealed behind Danish cord in the end.

I got a start on shaping the parts next, routing all interior edges with 1/4" radius, and 1/2" radius on the exterior edges of the rails.  The exterior edge of the stiles will be given a 10 degree bevel on the tablesaw so that the surface will be parallel to the edge of the arms.   That's on the menu for tomorrow.  For now, just a dry fit of the backrest so far.

I decided against trying to router the round-over on the stile ends.   That is a recipe for disaster.  Instead, before glue-up, I'll nip off the corners at the bandsaw, and then blend it in to the rails after glue-up with a rasp.