Way back when, we discussed tractor magnetos and grounding out spark plug wires that were not being used, such as when using a 4-cylinder mag on a 2-cylinder engine.
A friend is working on a mag for another friend right now. It is a 4-cylinder Robert Bosch for a Hart Parr. Bosch has looked after the unused leads. He says there is an "air gap" where you can see the spark being made.
His question is, is it better to allow the unused wires to make a spark somewhere, or does it do just the same thing to simply take them direct to ground.
Do they need to make an actual spark for the betterment of the coil, etc.?
Thank you for any thoughts.