I have made some plug inserts. MVVS also makes them by now. You also would need a different prop drive washer, because the latest ignitions have the magnets at 120 degrees, and not 180 degrees like the Vlach units.
It would be most convenient to get a new Vlach unit.
I must check if I have an opened unit arouns somewhere, and take a picture. That may help you to reconnect the sensor.