When I was putting together my P/J 5er I went with Dimarzio J and Fender P. A terrific sounding combo. And the P soloed really sounds like a "P". But be aware that they don't quite balance. The P is about 15%-20% hotter than the J. Some people overwind the J to compensate but I prefer to keep it all stock and just roll back the P volume a tad to get balance.
This is always the problem with P/J configurations. Getting a nice balance when both volumes are up full. The alternative is to get over or underwound pickups and then everyone complains that with pickups soloed they don't sound like a "real" P-bass.
Agree! - like this combo on my fretless. Just did this with a Franken' Franklin I pieced together. Model J is plenty hot enough though - just have it about 1/32 closer to the strings. Volume is balanced well with either solo'd. Some of us had phase issues with the Fender P and the Model J though. For me the fix was swapping the wires on the P side that had a phase issue. Here is final wiring diagram: