switch amperage rating is about only concern. A=W/V amperage is voltage divided into watts. 60 watt headlight at 12 volt is 5 amps. a 30 watt bulb at 6 volts is 5 amps. 45 watts is about highest common 6 volt headlight- that draws 7.5 amps. Amperage is flow rate that produces heat in wires- that is a concern. get a 20 amp rated switch and unlikely to have problems- what is actual bike and actual headlight, taillight, brake light, instrument load? .
Yes. Only possible problem, The 6V switch may be rated for a higher current, check the amps. This may shorten the life of the new switch, or you could insert a relay to take the current.
It's fine. A switch is...a switch ! The voltage is irrelevant. The 'current rating' of the switch in this case is also irreleivent.
Yes. That's no problem. It's the current rating that matters. (A).
I = E/R, dude.
