Battery Disconnect Switch

[Davew]

Going to install a disconnect switch in my 30 coupe. The previous owner moved the battery to the engine firewall. I'm thinking of mounting it either to the starter with the mount you can buy or the firewall and control it from inside. Question is, should I get a 2 pole, which I would hook up to the ground wire or a 4 pole so I could also disconnect the power going to the switch? Thinking 4 pole but not sure. That way everything would be cut off.