You got it. Whatever design you have, it needs to be protected from the battery. The starter is the exception.
The weakness of the MAD's idea is that it sends all the power through two fusible links.
What you need to do is
(1) trace the alternator feed. It should go to the main splice. That's the simplest and the best for basic electric (no efi or electric fuel pumps etc). Depending on your wiring skills and the condition of the bulkhead connector should determine whether you want to run an additional wire in parallel through a grommet.
(2) see if there is a second wire from the alternator stud to the battery or the starter relay. If so, then the PO arranged a direct charging wire from the alternator. It needs fusible link.
If you chose to reinstall a wire from the starter relay to the main splice, it would provide a shorter path for battery power during start up. But it too would need a fusible link.
