I just finished making the jig to cut the top angle of the rear leg. I got the idea of these jigs from a Chippendale sofa article in Fine Woodworking magazine.
As you can see, I glued and shaped the knee blocks that extend the leg letting it flow into what will be the seat area.
I spent a couple hours late last night making this jig. I rough cut the rear mahogany leg and the jig allows both rear legs to match each other. A second jig will have to be made to cut the top part of the rear leg so the angle of the seat back matches near perfectly. The things they don't show on New Yankee Workshop is how long it takes to make all the jigs Norm Abram uses. Once you make the jigs and patterns for chair making you can produce the next one much more rapidly.