Does anyone know the exact diameter of the wick spike that punches the tank cap? I want to make a punch. I've heard punching a hole slightly smaller than the spike in cap first rather than letting the punch spike it can reduce leaking. Which makes sense since there is a flap left behind after spiking it and must not create a great seal. Granted I am using 100% PG right now so I've sure the 70/30 I have on the way will reduce leaking as well.