The sides are missing for a reason. The Stickley design was to glue the sides onto the legs with the grain parallel to the legs and top. This means the grain on the sides is perpendicular to the lower stretcher but Schwarz observes in his article that he has never seen an original where this is a problem. I think this is because there is enough distance between the sides and the stretcher that the leg can flex enough to absorb the seasonal movement. Good enough for Stickley, good enough for me.
As is my custom, I drilled out the waste and then used a wide chisel to pare them smooth. Since these mortises are narrow (1/4") and deep (1 1/4") they were a little more difficult than usual but things still moved along nicely. In this case, I opened up the hole with a 1/8" chisel and then pared the sides with my thin, wide Wm. Butcher chisel, which was ideal for this purpose. The holes provide precise guidance and it goes quickly.
Some frown on this method and I did make an attempt to move away from it at Christmas time but, alas, both the Lee Valley PM-V11 mortise chisel and the Ray Iles chisel were out of stock. Fate I guess. I experimented with the Paul Sellers method of mortising with a bench chisel and it went fairly well but I found that I was invariably a degree or two off. That's too much so I would have had to pare the mortises anyway and Sellers' recommended method of using a guide doesn't appeal to me. I'm not sure but I doubt my method is much slower than using a mortise chisel unless you can reliably get them dead on with no adjustment. In any case it is extremely accurate. The dovetailed mortises in the top of the front leg were made by hand in the usual way.
The tenons were all made with hand tools, sawing the shoulders, chiseling off the waste and refining them with a shoulder plane and a router plane. Because the mortises are so accurate and uniform, it goes quickly.
I think a lot about what I view as a minimum set of power tools that I could be happy with. I'm down to three: a drill press, a bandsaw and a lunchbox planer. One of the nice aspects of my choices is that they can all be on mobile bases and require very little space--maybe 6 sq ft. when not in use.
Now it's on to fitting the sides, putting the curve in the front stretcher and tapering the legs.