Originally Posted by Ted Ewert

Hi Ben,
I like your circuits. You may want to try a Sidac in the gate circuit of you cap pulser. I used one that way and it worked great. If you don't know what they are, here's a general description:
The sidac is a silicon bilateral voltage triggered switch with
greater power-handling capabilities than standard diacs. Upon
application of a voltage exceeding the sidac breakover voltage
point, the sidac switches on through a negative resistance region
to a low on-state voltage. Conduction continues until the current
is interrupted or drops below the minimum holding current of the
device.

These are really handy little devices. They only cost about $.50 each and come in a variety of voltages. Much better than a zener in this type of application.
Littlefuse makes them and you can find them at Mousers.

Ted