I will follow up by saying that IMO, 90% of the split-coil style precision pickups out there are designed to follow the 60's style. IME, the Nordstrand is more "modern" sounding than the original 60's that is in the Fender '62 RI bass. If you want the 60's sound get the Fender pup, the Fralin or Lollar are also great pickups. Personally I like the 50's pickup, thus my offer ^^^. As far as balance is concerned, I think you can achieve good balance with both, and a lot of it has to do with your playing style, but the more common "flat" pole pickups are easier to achieve a string to string balance. IMHO IME YMMV etc.
"We're just normal guys trying to make interesting music." -Wayne Coyne, Head Flaming Lip