You've always got the option of ditching the balance pot and wiring the two coils in parallel direct to the volume pot. Then you could use the standard control plate. Or add in a switch to drop from both to one coil. They aren't far enough apart to make much of a difference in tone when using the balance pot.

Or you could even just use the balance pot to feed-in the signal from one coil, with the other bypassing the pot so that its always in circuit, so that one end of the pot travel gives a single coil, the other both coils.