I think the fuse-able link is there to protect the interior from the battery in case of a short, that occurs in an accident that crushes wires to the frame. The extra links "probably", will increase available amperage.
I also think that the amp meter that never goes over the 50 amp line, shows that the car needs no more than 75 amp. alt.
I upgraded where needed, but still run the amp meter and I have a new volt meter to swap into my 1968 cuda. On my 74, I just put a thicker alt. wire (75 amp) and extra fuse-able link wire to the interior amp meter, for now.
I have some relays for the lights to play with. That's a good idea too.