Every aircraft is unique. It depends on what type controls you put in, where they are located, what type of induction system you have...all kinds of stuff. I'd suggest you mount the engine and go from there. Yeah, the 8 probably has less variation than other models, but you really want to be precise. Another builder recommended using 1/4" plastic ice maker line to approximate the position and routing of each line, as it bends about like control cables will. You can mark on it with a Sharpie, then measure when it's stretched out. That's a whole lot easier than bending a tape measure around or guessing.
As far as a source, I think I got mine from Aircraft Spruce. But I'm not positive.