I appreciate your feedback, any more insight would be helpful. Do you prefer two J's, how would three sound?
It all depends on the execution. I don't mean to cop-out, but a lot depends on the bass itself, the pickups, the choice of wiring and controls.
I can tell you that my 3-pickup bass sounds phenomenal. I have three Fender Super 55 J pickups (one bridge, two neck). The body is a Warmoth. I had them route the bridge pickup in the normal location, and then route two neck J's with 2" edge-to-edge. It was a completely arbitrary number, based on how I thought it would look.
(Caveat: many people hold to the theory that pickup placement should be related to harmonic locations. I am not one of those people. Harmonic locations change the instant you start playing up and down the neck, and there's absolutely nothing anyone can do about it, so I choose to ignore it completely.) (And even people who do believe that theory say that it doesn't matter if the pickups aren't located precisely.)
The pickups are all wired parallel to each other. Each one has independent volume and tone control. From there, the signal goes to a Turnstyle switch, to a master volume and tone control, and on out to the jack. It is all passive. The Turnstyle is a 6-position rotary switch -- position one is full manual control of all pickups, positions 2-6 are tone presets.
Michael at [Invalid or Expired Link Removed], who did the control circuitry, had this to say:
"I got the neck on it and WHOA does this bass sound good!! These pickups not only sound amazing but work exceptionally well with the Turnstyle switch. Even if these were not noise canceling, they would be worth the price just on tone quality alone. The clarity of them reminds me of the Fralin pickups I have in my Tele.
The setting with everything wide open is crazy sweet sounding. Reminiscent of the Seinfeld J-Bass tone but the middle pickup adds a whole new complexity to the tone without even the slightest hint of mud.
One-of-a-kind bass with infinite tonal possibilities."
So to answer your question, three J pickups on my bass sound exquisite. I love having three pickups, it gives me a lot of tonal flexibility. I invite you to try three J's. Or how about two J's and a MM? The possibilities right now are only limited by your imagination.