top feed from swirl pot is always to tank, this is to stop pressure build up and rid of any air in the system.
with a sufficient lift pump i would agree that there would be a decent flow back to tank, so i see no issue with retuning from fuel rail to swirl pot. i did run a test after idling for abot half an hour and temps did rise a little to be fair, just over 30 degrees. with the inlet being warm and fuel rail itself getting hot due to heat soak i didn't think there would be much of an effect doing it differently.
more to the point you'd have to make sure your lift pump is bigger than the injection pump, as in flows more.
more importantly if there is fuel surge in the tank for a few seconds, then the lift pump won't be filling the swirl pot, but the injection pump will be draining it quickly.
best thing is to try it different ways and see how it works best for your requirements.