Thanks, Charles, for the education and for pointing me to the the previous go-around on this subject. That's the one I was looking for, but couldn't find. It is now copied and filed.
I'm dubious about my repair to the frame horns where the sway bar saddle brackets attach. The repair consisted of welding on 5x3x1/8"plates - welded not only at the edges, but also through five 3/8" holes drilled into the plates. It's tricky to get a good weld there without flipping the whole car over, but now that I know that it is a problem area, I'll keep an eye on it, and if and when they fail again, I'll do a more solid job.
I considered reinforcing the "ears" on the lower control arms, but that was only after I had them all prettied up and painted again, so I'll leave that for next time as well. Locating the sway bar linkage more to the center of the control arm makes a lot of sense. I suppose that distributing part of the stress to the other side of the control arm would help as well, but you'd still get the twist effect.
I grooved as much of the cracks in the spring perch plates as I could and filled them with welding. I also welded the whole length of the joints between the channeled arm and the spring perch which originally was attached with three largish spot welds. Thereafter, I welded 1 1/4 x 3/16" flatbar over the repair areas, making the welds about 3/8" wide and feathering them as best I could. If this doesn't do the trick, next time around I'll cut plates out of 3'16" stock and bolt them on top of the whole control arms, leaving space for the springs, the rubber bumpers, and the sway bar linkage ears. Meanwhile, I'll keep my fingers tightly crossed, hoping that none of this will be needed. ;-)
Bob S.