I would not worry too much about switches. Just get one big enough to be used with winter weight gloves on. If you feel it getting warm use the next size up. DC switches are sometimes 2 and three times as heavy as A.C. switches as low voltage meant higher currents meant resistance heating. That is why Westinghouse beat out Tom Edison in wiring New York and the rest of America. And get outdoor grade AKA water-proof switches.