For 35" scale you just multiply all the numbers by 1.029. It's not a huge difference, but all same points apply.
2 1/8" becomes about 2 3/16" and so on. I don't necessarily hear a change of 1/16" personally. But the difference is cumulative.
My moving PU mechanism will allow for adjustments in detented increments of .125" and a total travel of 1", from bridge coil at 2" to bridge coil at 3". So I'll get all the fender spots, plus a bunch more.
To your point 1 response, you have the coil that is in the neck position at the J-bass spot. But the way these kinds of passive PU's work (forgive me if this is old news to you...it's not to some), in order to hum cancel, you pair a North magnet (bridge) with a south magnet (Neck) but the Neck is an "up side down" wind. So any signal generated by a combination of the magnetic field and the electrical coil is inverted twice relative to the bridge PU...or 360 degrees out of phase...or in phase. But the noise is only effectively being picked up by the coils independant of the magnets. So the noise is 180 degrees out of phase. So when the two PU's are blended, the noise is in each one backwards and hence gets cancelled.
The catch with the dual coil thing is that the "inner" coil of a bridge PU is wound the same as the outer coil of a neck PU. So if you use only the coil on the neck PU that is in the correct spot, when you blend it with the "outer" coil of the bridge it's fine, but if you blend it with the inner coil of the bridge, you get lots of noise (more than one coil alone). If you reverse the polarity to cancel the noise, you also put your main signal out of phase.
Cool... I did not know that. Thanks! Makes sense.
I look forward to hearing you in concert sometime with your new bass. The old one sure sounded darn good