Coil for a car will work,ive seen it done...values are all messed up and its kinda huge so not even thinking that path,and as you say they are 12v start up and 8v Running.
What I actually had in mind was the 'pencil coils', used one per plug on some late model cars and motorcycles. These look like a very long spark plug cap. Not a full size car coil, either from a coil pack or distributor ignition!
The actual coil in these is very compact. But the car units are still wound for 12V input, not the 200V+ the Magister feed coil puts out. Apparently the motorcycle pencil units are wound for ~500V input from a CDI, but that is on the other side of the wrong turns ratio for the Magister system.
