I'm probably in a distinct minority, but I don't think there's any functional difference between a split-coil P pickup and a split-coil J pickup. And I don't think 1/4" difference in placement makes a discernable difference either.
Of course they are variables, but IMO they are insignificant variables when compared to differences among the many variety of P pickups available, and among the many J pickups available.
The original split P shape wasn't about tone, it was about eliminating hum and accommodating the raised A & D strings. If Leo had the wherewithal to put the two coils in line originally, there never would have been a P pickup in the sense we know it.
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