also i know the switch and relay can handle a set of lights but if i wire it this way will it be able to handle two sets of lights on one switch for my kc lights on top of my truck or will they have to be wired to two diff switches for 4 lights?
you can run as many relays as you want off of one switch. I wouldn't put more than 4 lights on per Relay, depending on the load. How many amps is each set fused at? and How many amps are your relays rated at?