The fat red wire you can run to any location that is hot, even the alt output stud if you want. It is nothing but a feed for the box. Although it may be better to pull a larger wire forward (noise buffering from battery) from the battery/downstream side of switch to a bus point.

The "important" wire is the small red trigger wire. That wire needs to be on your downstream side of the cut off switch. Cut off thrown, box goes dead, no signal. Putting the fat red on the same side also cuts of operating current.

Just depends on the approach you wish to apply.