This latest EFI system I tried something a little different. I mounted a return style EFI regulator right next to the fuel tank on my '69 GTO, this lets me use very short supply and return lines. I have an in-tank Aeromotive pump. The main supply line then goes to the front of the car using steel -6 AN hard line. I find the -6 AN is the largest tubing I can bend out of steel using my bending tools, and is plenty large enough for my HP needs. There is no return line other than the short piece of push lock hose in the picture.
I was a little concerned about this as the regulator is quite a distance from the EFI throttle body, so I put a pressure sensor right at the throttle body connection. Once I got the car running, I data logged fuel pressure and I see rock solid pressure with no (unusual) spikes throughout the load range.
If there is a disadvantage, it is difficult to access the regulator pressure adjustment screw, but you only have to set it once. The advantage is that it does not require a long return line, and uses fewer AN fittings . The cost of these fittings is surprising- it adds up and can add hundreds of dollars to an EFI install.