Creating the back mortises was probably made a bit more difficult than it absolutely had to be. However, one thing led to another that worked its way up to 6 clamps, a straight edge, and a roll support. Apparently, the straight clamp doesn't work very well on non-straight sides. I'll have to remember that for the future. Eventually it did work and I got the result I wanted. Was also able to glue up one of the front legs...