In which sub-kit ...
I did get one length of the copper bus bar somewhere in my kits, but darned if I can recall which one. I'm wondering if it was in the fuse kit, since you end up installing the starter and master solenoids on the FW relatively early in the fuse construction.
For another use, I later ordered one of the brass buss bars from B&C. It was thinner and less "preferable" than the thicker copper one from Vans.