I needed a new electric pump to replace a 30? year old pump. The new pump was the same make and model as the one it replaced, but it put out more pressure. The carb did not like the extra pressure, so I added a 12-803 regulator and gauge. This regulator has 2 outlets - perhaps you could have one pump feeding two carbs? I did not have to add a return hose to the tank.
Before connecting it to the carb, I ran the pump with the hose discharging into a gas can. This primed and flushed the system.
