another amp meter bypass question?

I upgraded my dash and installed a volt meter. (see pictures). I took the black and red wires at the old amp meter and soldered them together right at where they were located for the amp meter. Installed shrink tube and then taped over for a good connection. I installed the volt meter by taking the feed from the blue ignition wire and then grounded the other side along with the other gauges I installed. I have a brand new M&H engine harness with the correct fusible link on the red wire which goes to the starter relay. Because the engine harness is brand new I also have the heavy black wire, which when plugged into the main dash bulkhead it aligns itself with the black side which use to go to the other side of the amp meter. I understand I need to run a black 10 wire from the alternator to the starter relay and install a 14 GA fusible link on this wire at the relay. Somewhere I am losing what happens to the black wire already installed in the new harness when I plug it in to the bulkhead connector black wire?? Do I need to do something with the black connection at the bulkhead, or do I just leave them plugged in as they would normally be? I don't see any fusible links along that black wire in the new engine harness. So is the link I am installing at the starter relay an additional link protection?