Ok, so when flipping, we do get a pulse from the hall sensor, but what is the offset between the rising edge of the sensor and the desired time for the ignition?
Most if not all model aircraft engines produce a spark when a logic 0 is seen at the ignition board. So I think the best thing to do is have your code look for a low going pulse and then start the timer or what ever. So I guess I am saying as soon as the magnet reaches the hall the signal goes low. This is where the spark needs to occur.