If You want to keep the original Material stay with the copper coated lines. if You have the rectangular channel beside one main frame tube and need to keep the emission lines as well maybe You dont have the room inside the channel for 2 braided hoses plus the emission lines.
I normally use plastic covered aluminum tube 10mm OD and close to 8mm ID from the tank to the engine bay or firewall position, this is enough for any fuel injection. From these tubes up to the carb or EFI unit I use the dash -6 braided hose.
You can buy these fuel line tubes at any race shop in Europe, they are connected to any -6 AN fitting by cutter type rings and a tube to AN adapter.
With these aluminum tubing You shouldbe able to run a new, durable and easy to install delivery and return line in a limited package inside the steel channel or beside the frame