red source coil air gap?

how important is the air gap on the red source coil and where should it be.I raise the coil all the way up and lock it down.

i raise it as high as it will go... never had a problem like that, and you're more likely to not kill the coil if you ever bend the crank.

Not 100% sure it's correct but I always set mine with a business card. Never had any issues either.