Yes on warm fuel returning to tank!
I know the older 12Vs return allot of preheated fuel to the tank, I know 24V do also, just not sure how it compares. On a 12V, I would say once runnning you will not gell (fill up with staight #2, engine warm and drive). I did this many, many times coming back from KS to ND. I would fill at Sioux City with temps just below zero (no blend either) and drive straight through to ND with temps as low as -28. Lucky... . maybe! I have an extra 40 gallons in the box that gravit feeds to the main tank. It would even flow enough to drain.
I think between the fuel filter heater and the returning fuel it keeps the fuel temp from dropping much. Stop and sleep for many hours and that would be a different story.
I have not ran any #1 (even blended with #2) in 5 years. Going to wake up to -25.
jjw
ND