I would try to stay return less for something that gets driven a bunch.

I run a return EFI system on my 68 and I have enough fuel pump for about 550HP and a second pump staged for back up. I have problems with heating the fuel when driving around town or extended highway drives. Because it is returning so much fuel back to the tank from the hot engine compartment it heats up the whole load of fuel. I even added a small cooler with a fan on the return line.

My EFI system can handle PWM control so I am going to think about trying that to reduce the amount of returned fuel under light load conditions.

The fuel heating issue is the only thing I have not been happy with after going EFI. It has never stranded me but the pump sure does scream when its pumping hot fuel.