There's just one hard supply, one hard return, they follow exactly the same path before transitioning to hoses. If you look at listings on Bring a Trailer, people will frequently photo the underside on a lift which should help you with routing. Does you car have the sheet metal tabs still remaining on the underside? Even if they're broken off you ought to be able to see where they were welded in place. Also, with some common sense you don't need to replicate the routing 100%. Wandering an inch left or right is probably going to be okay.
I know at some point I measured them to make sure I ordered enough NiCopp. I could probably search for that order to see. But again once you know the approx routing, from pix etc, just tape some string to the underside of the car and you'll get pretty darn close to the length. All this presumes you are making the lines yourself or the person who is making them has the car at their disposal to bend-fit-bend-fit.
When I replaced mine I ordered a 20' roll of stainless steel tubing. Since my car has carbs, I only needed 1 line. I had enough to do both lines and gave the extra 10' to a friend. Hope this is helpful.