I think this diode added right here (D5) would do what I'm looking for. It would keep the SCR on and would recover the spark energy that came back through the cool. I think an SCR is the best thing to use though, I believe the SCR shuts off too soon if you have anything besides a bridge rectifier. Pin 3 is the coil positive and pin 4 is the coil negative.

 

This might be a daft idea, but perhaps not - if you use a MOSFET or IGBT perhaps it can be switched off at just the right point on the ringing waveform to leave the maximum amount of voltage on the capacitor. Sort of like a Quasi-resonant flyback converter in reverse.

I see what you are saying, keeping the voltage in a useful range. There really isn't a need to drain the capacitor down to zero volts when nothing below 150 volts would jump the spark gap.