I'm no expert, but I've converted my truck to 12V successfully. Ultimately, you need to go back through the conversion steps "in reverse":
http://www.stovebolt.com/techtips/12_volt_conversion.html From my reading, understanding, and experience:
1) If your coil has an "internal resistor", you won't find (and don't need) the voltage reducer you're looking for.
2) Nope. You need a 12V battery in a 12V system. (you'll either not get the charging system to work on that low a voltage, or you'll cook the battery if it does); Most folks (including me) run the 6V starter on a 12V system. My understanding is there are different starter pinion gear sizes between a 6V and a 12V that would require a flywheel change to make a correct mesh.
3) You'll need a 6V coil if you convert it to 6V. As it is, you need a 12V coil (not sure what to make of the apparent coil temp, maybe it doesn't have an internal resistor and needs one).
4) 6V coils aren't offered with internal resistors - they don't need them (assuming you're running in a 6V system).
I'm sure that others will have additional thoughts or comments.
Good luck and best regards,
Bill
