I used AN fuel line for the return and supply. I was going to use hardline but didn't have enough confidence to bend all that line from tank to motor.
I used some of the profits from the sale of another car to purchase the line.
Others have used different adapters for the an line to the fuel rail/regulator. I got some from John (can't remember his last name) I think he owns John's Powdercoating. He is in Kentucky and is a super nice guy. The adapters were for the rail, regulator and the tank. No leaks, no problems after 2 years.
Do a search for " fuel line adapters hybrid " you should find one of my old posts.