6 or 12 volt ?

[rampant rivet]

I am getting near to firing up the engine on my C 15 and need to buy an ignition coil, battery etc.
If I take the 12 volt route what are the pro's and cons regarding keeping the old generator etc ?
I have a new 6 volt starter motor which may or may not run on 12 volts.

Any info gratefully received.

Regards RR.