Perhaps you've already sorted this out but, when you mention "P position," are you referring to the treble (G and D strings) coil in a split P, the bass coil, or the center-line between them? I guess you could also reference the old, single-coil Precisions, if you dig that sound, but I'm not sure of their placement relative to a split P.
In any case, it would be worth making sure that you and Joe are on the same page about it.
Good luck -- I hope that there's continued and conclusive positive movement for you with your bass!
Hey just saw this
The soapbar shells are exactly the same size as standard p bass halves...so right next to each other they align with P pole pieces perfectly (peter piper anyone?).