I just buy a 12 or 18" hardline from PepBoys. Comes with the metric bubble fittings already on it. I have a set of 3/16" bending pliers for the tight turns.
I just used to replace all the shitted up lines behind the firewall on a lot of gm cars with that stuff. Once the cancer starts its hard to find a hard line to splice into. I would just go the whole length of the car with that easy bending stuff and be done with it.