You could use one of these.

http://www3.towerhobbies.com/cgi-bin...?&I=LXK135&P=0

This allows you to have only two fuel lines. Mount it on the cowl or inside the cowl to fuel.

I am doing this with my new cowled model but I'm not sure how I will know when the tank is full when I cannot get to the exhaust line? Someone said when you use an electric fuel pump you can hear the pump change pitch as it reaches full?