When getting a set of say SD Vintage Rails pickups or APSs are the neck and middle pickups interchangeable or are they different pickups? Sorry if any one gets cofused by this.
In my Strat with the Antiquity Texas Hot Custom bridge and Antiquity Surfer neck and middle I had to swap the positions of the neck and RW/RP middle in order to get humcancelling when the middle was combined with the bridge pickup.
If you're putting together a set of two or three differant single coils and want humcancelling when the middle pickup is combined with the neck or bridge, the neck and bridge pickups need to have the same polarity and the middle pickup needs to be the opposite polarity.
Just check by placing them against each other and see if the magnetic poles attract or repel each other. If they're the same polarity they'll repel. If they attract, they're opposite polarity.
I also had to reverse the white and black wires of the bridge pickup when I put that Surfer/Texas Hot set together.