Everybody seems to think that you can't have blending when your pickups are in series. However, I've drawn out a schematic that will allow one to have a series/parallel switch that still uses the blending pots when in series mode. In this picture, the first circuit is the one with switching that you should follow. The second two circuits show the results of the switch in each position. The numbers indicate that a wire should connect from the switch to that point--all drawn wires remain intact. As you can see, the volume pots are basically considered as part of the pickup, and are incorporated into the switching. Let me know what you think!