Ok, so while I was installing my stuff in the new car today, I discovered that the "0/1AWG" ring terminals I got off eBay are too small. Way too small, because I was unable to fit the 0/1 awg wire into them. They're also so stiff that I couldn't crimp them even if I could get the wire in.
So now I'm going to have to venture out to Home Depot and hope they have some actual 0/1 awg terminal connectors or I'm going to be royally pissed. On the plus side, the battery in my car is located under the rear seat, so I don't have to run the wire very far at all (which also means no drilling a hole in the firewall - YAY!)