Hi Jon,
I would like to know the necessary current flow across the ignition wire. It's quite easy to build a step-up converter to the desired 12V.
If you like I'll make a complete circuit for you including an extra safety feature like dual ignition buttons, far enough apart, not to initiate ignition inadvertantly, being forced to use two hands to operate the ignition circuit.
I've been model rocketeer for quite a while and even small rocket motors can cause severe injuries to persons standing near the launch platform.
For the ignition wire I usually use wolfram.
Regards
Boncuk