Use a relay.
You could get switches big enough, but the problem is voltage drop. The longer the cable is the less power will get to the plugs. Mostly the wires from battery to plugs is about 1m, so there is minimal drop. If you used a switch you would need to go from battery to dash back to plugs. Relays are cheap, get one like the use on electric start mowers, they can handle a few hundres amps, it will make it last far longer than a standard switch and you will have a shorter wire run. My 743 has a relay just below the air filter, so battery, relay then plugs.
With a setup like this, a fuse will not be required. If you needed a fuse, you would need in the order of 30 or 40A or possibly more, they do chew the juice.
