I am using a RS 1 for the bass and a home-made piezo for the click. My home-made Rockabilly pre amp gives each pickup a 10 meg ohms input impedance. Then the clicky pickup goes through a high-pass filter that cuts all the low end from the clicky pickup. There is one knob that adjusts the volume of the clicky from silent to full on psycho the 2 pickups are blended and exit on a 1/4" jack that turns the unit on and off.
Here is me modeling the package to make sure everything fit
the PCB layout
Here is a mock up with the real case
here is a peek inside the finished unit with a pack of cigs for size comparison

The thing sounds awesome! I will try and get some photos of it mounted to my bass.