FWIW I tried a return system on my street car, ie pump gas car thats not used alot. After having to replace the return line for what would have been the third time, in 8 years I decided to NOT use the return regulator and line(mounted near carb) and just use the pump bypass. No ill affects, no issues in traffic in Vegas heat and no difference at the track, been like this for 14 years. Pump has been in the car for 22 years....Never had to touch it.
Same here, pumps been on the car since the 90s.
If I went back to a carb I would run the single line to the carb and let it eat.
