Do it like this. Two fuel dots on the side of the airplane - both connected to splitters. The overfill line has a check valve that allows air to fill the tank as it is emptied, the tank is not pressurized. The "fill" line is branched off to a fuel filter (the big silver thing) which then goes to the pump.

And no, you don't need muffler pressure. I use a tapped backplate and it works perfectly.