You know, Nick my youngest and I were discussing that very thing with the 3 nipple fuel filter.
I already ordered a 3/8 sender and it has a 1/4 return/vent nipple on it so that wouldn't be too hard to do.
If we use the current supply line as a return, would you still move it out of the engine compartment to keep it from pre heating the fuel on it's way back to the tank?
Or am I over thinking it??
I'd just use it as is for now (I'm basically lazy), I don't think you'd have any issues using like it is as a return. Any vapors just vent back into the tank. Just make sure your tank is venting properly.
Just remember that with most, if not all, repro fuel senders there are issues with the sender accuracy. Not a huge deal, just be aware.