The GK-3B is perfect for Roland VSystems, but useless as a hexaphonic audio signal pickup.
I want a breakout box to isolate all 6 strings into 6 amp channels without crosstalk,
GK pickup coils share a common earth so crosstalk is unavoidable,
and even if there were a breakout box for the GK, the impedance and inductance is way to low on those tiny coils.
The pickups mentioned above however can do both jobs.