All tank and plumbing accessories must be gasoline rated. Items rated for nitro use only will degrade with gasoline.
A felt fuel clunk is the best option for a gasser as it constantly picks up fuel and ignores the air bubbles right until the tank is dry. Use the felt clunk that comes with your engine.
The popular coloured Tygon fuel line can cause problems with 3D/sports flying as the internal tank pickup line.
Use the black soft neoprene fuel line that comes with your engine as the clunk line which is softer & more pliable unlike the Tygon fuel line that has the potential to get stuck within the tank. Make sure your line has enough length to reach all points within the tank. Tygon fuel tube can then be used externally to connect the tank pick up to the carb intake feed & also the return/prime line. The fuel return is positioned high within the roof of the tank & is connected to the primer/return nipple on the carb. Obviously the other nipple on the carb without the priming bulb is the feed or fuelpickup line.
Tygon tubing degrades over time. Check the tubing periodically especially at the end pipe /clunk connections where the tubing has been expanded & stressed.
The tank needs to be vented to the atmoshere. To prevent fuel spillage whilst inverted use either a breather valve or a length of fuel line looped 2-3 times.
Fill the tank via the return line & drain via the filtered clunk pickup line.