You use the battery terminal ends that support multiple wire attachment, so with your's I would go from the buss bar to the negative cable end. In post #318 above, I have a picture of a multi cable terminal end on the positive side. I don't have a dedicated ground buss on this car so only the positive end is shown, but on my K20 project that uses multiple buss bars, the negative and positive ends are both multi wire capable. If you don't want to invest in cable ends, you can drill a hole next to the buss, install a rivnut and bolt and as long as your ohm meter reads 0 between the bolt and the negative battery post you're good to go.