After an absurd amount of experimenting with P/J's, I finally settled on a few conclusions about them that work for me. The following observations are my opinions only, and may have little or great value to anyone else. But, that being said...
The Dimarzio Area J makes a great bridge pickup when combined with a vintage wind P pickup. The output level is good, the lack of hum is even better, and it sounds pretty close to how I like a single-coil Jazz pickup to sound.
My favorite configuration is Master Volume, Master Tone, 3-way switch. I used to fiddle around with rolling off a little of the P pickup, or a little of the J pickup, but over time, I found I used those sounds less and less. A 3-way makes it a lot simpler. Plus, having the option to get to the P pickup by itself, quickly, without fiddling with knobs, is invaluable to me.
A P/J is not a Jazz Bass. It's a Precision with a little Jazz sauce ladled on. If I want a true Jazz Bass vibe, I play a Jazz.
HTH