Pre bent line or do it myself?

No need for stainless if you run DOT 5 silicone in the system from day one. Most of these original lines rot from the inside out from moisture wicking into the DOT 3 and lack of MTX plus the fact that most of this old stuff is pushing 50 years old or older. My 94 silverado is now 26 years old. Dot 3 fluid system. Every couple years I power bleed it with a mityvac until the fluid comes out clear from all 4 bleeders. I have owned the truck since new. This replenishes the system with new fluid. Honestly I dont think if the system starts off as dot 5 silicone you would need to do any drastic measures. BTW all the lines in my truck are OEM except for the 3 braded flex lines.