Wiring Afterburner To 2 Passive Pickups

[Sepultallifly]

Normally I use nothing but EMGs in every guitar (81s & 60s) and every bass I have (40DCs & MMCS 5s). But I'm building an SG for a sludge metal album I've been wanting to do, and want passives for it. I'm going to be using a Duncan Invader in the bridge and a Tom Anderson PQ3 P-90 in the neck (Pepper Keenan setup). I want to use an Afterburner in place of the tone pot (only controls will be a single master volume knob, 3-way switch, and Afterburner), wired into both pickups. How would I go about doing this? I know you can install the Afterburner on passives, just curious as to how to wire it up. And since both pickups are passive, would I still need to have a ground wire connected? Thanks for any info/diagrams!