Duh...now I got it (big light bulb coming on). That was a great tip.

I swapped the springs on the front brakes from right/left and that solved that problem.

I still don't know what to do about centering the rear brakes. This set apparently has no centering adjustment. I have a new pair of Tektro Oryx canti's that are waiting to go on my wife's new frame. I tried to put them on but they would not go on the posts all the way, nor do the springs line up with the hole in the posts. It almost does, but appears just a bit off. I thought I read somewhere that newer canti's are not always compatible with older frames

Perhaps I'll try a cable hanger that crimps to the straddle wire.