Properly adjusted, the output is very even, but with very different tones of course. And I don't have to bury the P or have the J kissing the bottom of the strings to do it.
The Nordy P is fuller range, and tighter bottom than a typical early sixties P sound. I you like a wooly bottom, you will probably not like the Nordie. It is less peaky than say a Fralin, but reaches higher. Overall, I would say it is a more modern sounding P than the Fralin. If you are doing rock, r&b, or anything where you want tight and punchy, this is great pickup. If I were doing trad blues or country, I would probably prefer a Fralin. Just for your information, I tried a Fralin and a Nordie in my 60th anniv. P. (Also the stock CS p'up, of course.) I most definitely preferred the Nordie. But tight and punchy is my thing.
As for the Big Split, it is an animal unto itself. It is definitely in that modern super-j vein. Don't expect vintage j sounds from this guy. It has a wider aperture than a J which means it sense more of the sting. I think this accounts for a large part of it's sound. I have mine in the 70's position. It can definitely get that j-bridge-soloed snarl ala jaco, but I can also add a lot more bottom my moving my right hand over the P p'up. Together tThe warm mids of the P tone sit nicely in the center of the scooped J sound. It is a unique sound, and very useable. I will try to get a recording posted by the weekend with some samples.