Installing ignition relay

Another thing I’m wondering about is protecting the remaining charging circuit.

After I install my ignition relay, I will have done the following modifications:

1. Jump wire from alternator to battery with fusible link
2. Remove ammeter and replace with voltmeter
3. Headlight relay
4. Ignition relay

How do I protect the factory charging circuit? Obviously the fusible link didn’t protect it, because the wires were all melted together at some point. With my jumper wire I understand that the current to the cabin is now divided equally between the red and black wires entering the cabin, the former charging circuit.

How do I protect those wires? Should I add inline fuses between the battery and the bulkhead connector, as well as between the alternator and bulkhead connector? If so, what amperage?