Carefull with the 12V running to the ignition coil. If the coil is not designed to run at 12V then you will overheat it. The 6V you measured sounds a little low to me unless the coil is from an old 6V system.
Often ignition coils will have something written on them to indicate the working voltage (6 or 12) and they should also indicate if you need to use an external Ballast resistor or if they are "Internally Ballasted". The Ballast resistor limits the current that is supplied to the coil. If its internally ballasted then you simply run straight power to it. If it's "Externally Ballasted" you may need to put a resistor in series with it. Not a big deal as these are available at many auto parts stores.
Best of luck,
John
