The simple answer is that ALL Harmonic Design pickup sets include a reverse-wound pickup for Hum-cancelling in the 'both pickups' switch position, you don't have to do anything special, it's the only way we make them.
The full explanation is a bit longer:
-SOUTH - The end of a magnet that points to the Earth's South Pole.
+NORTH + The end of a magnet that points to the Earth's North Pole.
This 'industrial' designation is used by pickup companies, vintage test equipment and the $10 polarity testers used for guitar pickups. (Note that this definition is ass-backward from the magnetic field of the planet Earth and modern test equipment.)
We measure the magnetic polarity over the top of the coil, the side that faces the strings. In the case of humbuckers, we're referring to the polarity of the adjustable coil.
HD pickups magnetic polarity:
2-pickup sets = neck SOUTH, bridge NORTH
Strat sets = neck and bridge south, middle NORTH
When mixing pickups of different brands there's a 50-50 chance of a 'match' in phase. The traditional method is to install each pickup, plug in the guitar to check the phase by ear, and then rewire as necessary.
(Note that simply checking the magnetic polarity can NOT determine if pickups will be in-phase.)
There are only two possibilities for output polarity from any magnetic pickup, but that depends on the exact combination of a long list of variables in addition to the the magnetic polarity, including the design, construction, winding direction and internal wiring. But all we need to know is the bottom line: the actual polarity of the output, either positive or negative.
"Harmonic Design" Designation:
We've developed a simple test and definition of output polarity of any pickup.*
Our definition and testing method will determine the actual output polarity of any pickup (positive or negative) whether on the guitar, or before installing the pickup. From that, the resulting 'phase' between any pickups can be determined in advance. Any pickups with the same output polarity will be in-phase. Any coils with the same output polarity and opposite magnetic polarity will be in-phase, and hum-cancelling.
Many pickups (including all HD models) allow inverting the output polarity by reversing the pickup lead connections.
*By measuring the polarity of the D.C pulse generated when a pickup's magnetic field is momentarily dipped by switching off a compatible external magnetic field.
We'll gladly test and verify the output polarity of any brand pickup sent in with return postage.
Simple specs for HD pickups:
1. All pickups are negative output polarity. (white wire as output)
2. All neck pickups are south magnetic polarity
3. 2 pc. sets: bridge pickup is north
4. Strat sets: middle pickup north
Here are some measurements of other brands showing the (Industrial)
Magnet polarity and the (Harmonic Design) output polarity.
HD (3) south, -out (white) north -out (white)
PRS (3) south, -out (blk) north, -out (wht)
McCarty (1) north, +out (same)
Gibson (1) south, - out (same)
Gibson (4) south, -out (red) (same)
Dimarzio (4) south, -out (red) (same)
Duncan (4) south, -out (blk) (same)
Duncan (1) south, -out (same)
Fender (3) north, -out (red) south, -out (grn)
(number in parentheses = number of conductors in cable)
PRS P-90 north - out south
Gibson P-90 2007 north - out
Gibson P-90 1956 south + out
Duncan p-90 south - out
Duncan strat south - out
Pro II tele neck north - out (rwrp??)
G&L tele style: north + out, south
1988 A/S strat: north + out middle=south
Eric Johnson strat: south + out middle=north
1984 tele: south - out bridge=south