104 joints later and this suite of chairs is about is about halfway there. This project really makes me appreciate the square mortising machine we had at school, and I'm determined to find a similar solution for our shop after a week of this. The Festool Domino was a decent stand in for a horizontal mortiser, but squaring all the corners and cleaning up the rough surfaces left by the drill bit back to the scribed line was time intensive.
We could also use a tenoning jig, but it's easy enough to rig something up on an existing sled that it's not quite worth the investment, yet. These chairs are not glued, test fitting will allow me to adjust any joints that aren't perfect and pull everything together before we disassemble to stain and finish before final glue up.