Seymour Duncan has a diagram for that layout here, one pair of push/pulls controls both pickups.
I went a bit further when I used them and had four push/pulls so each pair could control the pickups separately, and added in some cap switching as well for the neck pup. That allowed me to have an 0.015uF cap on the neck whenever the series humbucker or P90 was selected and 0.022uF for the rail or parallel humbucker. Thread here and diagram: