Let me apologize in advance for the double posting. Not sure what
happened there. Sheesh!

I would have built another driver circuit for the additional wax potted
HEI's as I'm currently swapping the driver between the oil and wax
potted units, but one component in the driver is a rather large Hammond
5 H 150 mA rated inductor. Unfortunately, these start at $20 without
shipping. I guess it was no wonder I only bought the one originally.
Should anyone have ideas how I might make one, please share. Otherwise,
I'll be keeping an eye out for something cheaper.

I would have shared the schematic for this spark generator, but it
wasn't my design. It did appear a decade ago on the Tesla coil mailing
list.