Finally finished! It fought me until the very end. Last problem was that a chunk of wood I had glued against the center block was just wide enough to keep the jack from fitting. Fortunately this was fixable by using a thin chisel through to hole.
It sounds great! The pickup in the mudbucker position is nice and dark, but not muddy. The one in the middle position is very p-bass like. It has four distinct humbucking settings--the fourth is when both single coils are engaged.
Single coil sounds are good, but there's a little buzz. But in any humbucking setting it's dead quiet. I used shielded cable in the wiring harness and that may have helped.
Thanks to all who provided advice, counsel and moral support! I am very grateful for all of your help.