Generally speaking, you'll want one screw coil and one slug coil to be hum-cancelling. Series link wires to ground as Cagey describes gives you the slug coil, series link wires to hot will give you screw coil. Again, generally speaking. It assumes that the bridge and neck humbuckers are wound with the same direction and polarity. If they are reverse wound and polarized relative to each other, then same coils would hum-cancel. I wound the humbuckers for my Candy Apple Red this way for that very reason, hum-canceling with both screw coils.