Jake,
Just wondering with all this testing going on , how much would be entailed in writing a small program say for 12F683 that could take inputs from the hall effect and the existing micro output, take the time difference and with rpm as a reference, output degrees delay on an LCD display.

As John said earlier, playing in and around a spinning prop gets a bit iffy at times so just a thought to keep away from the prop with the timing light LED.