If you have a leak in your steel fuel line in one spot, doesn't it concern you that the whole line is on it's way out. When I restored my TR6 (and on my previous TR6, and, on my previous TR3) I found that the entire line was pretty crudded up. Not necessarily rusted (in some areas it was quite thinned out) but clogged, bigtime. One technique is to use a very long piece of tach cable and rout out the line with the end of the cable attached to a drill. Now, if the line is thinned out too much, this is not a good idea. Why not just go to NAPA and buy all new 5/16" steel fuel line and make up all new fuel delivery lines? Several of the joints are indeed often rubber (make sure that you only use designated as "fuel line", otherwise you will be asking for touble - usually Gates brand is dependable), using the self-tighening clamps, instead of the screw type, which will come undone and cause leaks. Now, if you car is a concours winner and you are worried about the perfect bend, etc., then often fuel lines come from vendors already made up, but you will have to dig deep.
Good luck.
Bill