Reading this thread has me thinking about an almost fool proof fuel system for low wing airplanes. The 1" connection between the tanks would assure flow the check valves would make the system use fuel from fullest tank. The electric pump would have fuel at all times with the head in the tanks. The shutoff valves are ganged to gather just on and off. Each system has its own filter. The engine driven pump has its own system. The check valves at the carb. or throttle body allow flow from the highest pressure source. I have seen engine pump failures that aloud the boost pump to pump fuel over board rather than to the carb.