Originally Posted by TheSaint
The barb is removed for filling, then refit the barb for flying, so that the tank remains pressurized.
The tank doesn't need to remain pressurized while fueling. You need to let pressure out before you fill her up anyway. After the vent line is plugged up, a few flips of the prop will pressurize the tank again.
I like to keep things simple and use 2 tee's and 2 fuel dots as my engine is also inside the cowl. Note the color coded fuel lines (red = press, blue = fuel):