which check valve are we talking about here? i have two of them. one is a metal one with an arrow on it and another is a small black plastic bulb one. do i use both of them or just one? which one of those is the pressure valve and which one is just the straight up one way valve?

also, have you ever tried dumping e85 into the tank instead of a methanol mix? it's just ethanol with a little bit of gas in it, so im fairly sure it wouldnt be a problem. im pretty close to finishing up my setup.