KISS...keep it simple stupid..
So then the debate comes back to, which side to run the switch.... my understanding is that it really depends on what your goal is.
If the goal is to cut all power in the event of a crash etc, so none of the electrical systems have juice flowing through them, then it should be close to the BAT and on the positive side. If you crash and things are all mangled, you may have created new ground points all over the place with shorted wires...and you don't want a bunch of hot circuits anymore
If the goal is more to be able to just essentially disconnect your BAT when the car is sitting, so the BAT does constantly get drained, then just put it on the NEG side