The ignitions I am most familiar with, using hall sensors, fire off the back edge of the magnet..Maybe 3W and others have found a different way...I know on mine and C&H the distance from the magnet to the sensor makes no difference unless the magnet gets too far away, then it just misses or doesn't work at all...Maybe a syncro spark module makes a difference, don't use enough to know..Most of mine are mechanical on large engines or fixed on smaller ones....I guarantee on mine it makes no difference as long as it fires at all....Some systems work off the diameter of the magnet, maybe 3w is one of those...