The kick drum is pretty straight forward, just one 27 mm piezo. I found a sampler pack on Amazon. My wire striper worked well on the tiny wires.
Once I put it back together it did not work, but when I tapped on the back of the bass drum it did trigger, so I took it apart again.
I have a strong suspicion that the problem all along was that the foam piece that sits on the piezo and rests against the drum head was not in contact with the head.
Once I added a piece of foam weatherstipping I had laying around it works like new!
So lesson, always check the most obvious first, I probably changed out the piezo for nothing but it was a learing experience!