It is confusing that the wiring diagram on Duncan's website doesn't match what's on the little schematic they send with the pickup or what's shown on Fenders website. Fortunately, either way will work just fine.
What the schematic ususally doesn't show is the proper grounding and hooking up of the bridge ground.
Here's a photo of it done the Duncan website way ..
1. Run wire from center lug of volume pot to tip lug (hot) of output jack.
2.) Run wire from back of tone pot to sleeve (ground) lug of output jack
3.) Connect bridge ground to back of tone pot
4.) If not using foil shielding also run wire from back of volume pot to back of tone pot. This will directly tie the back of the pots and bridge to ground.
5. Wire pickup ground (black) to back of either pot.
6. Wire pickup hot (white) to inner volume pot lug as shown.
7. Run wire from inner volume lug to inner lug on tone control
8.) Bend outer lug of volume control over and solder to the back of the pot to form a ground connection. Also solder one end of capacitor here to ground. Use a heat sink (I use small hemostats) to protect capacitor from overheating)
9.) Solder other end of capacitor to center lug of tone control.
10. Check all grounds and connection with a meter to make sure you have continuity.
YOUR DONE!!