I had some trouble with the neck. That's problem's resolved. While I was waiting I successfully destroyed the bridge pickup when I did the coil tap. I get the single coil working but the first coil refuses to join in to make the humbuckers The neck pickup is successfully tapped. So I now have some spares to play with.
I had bought Entwistle pickups that are already tapped. I have installed them on a pair of Seymour Duncan Triple Shots. These only work with humbuckers where the coils have their own wiring and the earth is to the pickup body, not the coils. The Triple Shots give you the choice of either coil as a single coil, the pair of coils in parallel or the pair of coils in series. I want to add a switch on the output from one of the pickups to swap phase with the other. I am also thinking about the option of the neck and bridge pickups in series or parallel.
With a pair of humbuckers the Triple Shots give 24 different tonal alternatives (4 neck alone, 4 bridge alone and 16 when both are used).
Phase reversal would add another 16. A choice of series or parallel as well would add 32, bringing the total to 72. Of course some of these would have similar tone, depending how balanced the coils are in the pickups.
I have been busy sanding. In the process I discovered I need to move one of the winder holes because it has been drilled about 2mm out of position so the line between it and the nut passes through rather than around the next winder down. Any suggestions for moving the hole. I will be cutting off part of the headstock so I could shape a plug for the hole or make shavings/sawdust to mix with glue to fill the hole.