old fuel lines and brake lines -Replacement Where and How? Tech tips please!

The nickel/copper lines usually have a drab green coating, they are rolled into a double wall tube from a copper coated flat roll of steel and run through a furnace that fuses it together they are soft and easy to bend compared to the original steel lines. They usually pressure test burst at around 2000psi, they are usually 4.76 mm in diameter. They work great and bend easy but are not original looking. Ive used stainless lines in the past which are great but a ***** to bend and hard to seal. My favorite lines are the OE style from inline tube.