I am not good at explaining so will try again.
On the battery cables they need to be thick to flow the current/amps but the rest of the bike electrical system is less than 30 amps and is fused with a 30 amp fuse.
On my bike i think that the negative cable was going bad so i just added another cable to it and that helped a lot.
When I upgraded my starter i never gave it a thought (until your post) lol
It works real good and might work even better with a better positive cable.