In my experiences a switch is a switch, but the ground is key, I would select a better ground than the bumper more towards the frame. You should use a relay for the lights, here is a WEB SITEthat should help you wire the lights with a relay. You're gonna use a standard relay, that you can pick up at any auto parts store.
A quick run down however would be this
On a standard relay you will have 4 or 5 post's to connect to, 85, 86, 87, 87A, 30, not all relays come with the 87A post.
Posts 87 and 30 are the load side(lights, fan etc) of the relay
Posts 85 and 86 are a low current side i.e. power coming from switch
You will wire a 12 volt source to leg 87 then the hot side of the lights to 30.
Then the 12 volts coming from the switch will goto 85 then ground post 86 of the relay.
STROKER MJ