Hello Cylinderhoner,
If the return line on your SR3 merely comes from the return side of the injectors as later models do, then the volume returning should only be a few drops per hour unless your injectors are very tired.You can either just catch it in a Coke bottle and pour it back once a month, or at the risk of fuel leakage from your gravity line, just tee it into the supply line ahead of the lift pump. On the basis of the K.I.S.S. principle, the Coke bottle wins my vote, regards, Combustor.