most indscent lamps can run on dc with out any troble but bear in mind that the dc verison will run slightly dimmer but not a whole alot but bulb life will be little longer too also.. i am not sure if you know this or not when bulb fail they do flash over pretty good btw just like 277 volts ac bulbs go out simuir idea so i dont know but i will guess you allready knew this or not put a over current device there to prevent serouis arc falut.
as far for switch use the genral usage snap switch .
merci , marc
p.s. i did work on one tug boat before it ran everything on dc before so i got pretty good idea how it react with it .
Pas de problme,il marche n'est-ce pas?"(No problem, it works doesn't it?)