Misfit,I would triple check on the seperate switch,as I read the state law here,auxilary lights must be seperatley switched,Rusty is the one for finding rules and regs for each state,I have lights on both of mine,one I have taken the switching wire from the headlight loom,the other I have gone back to the main switching box in the engine compartment.
Gonz as for extra loading this should not happen,your lights should be drawing their power directly from your battery,if you take your switching wire from the loom this power is only to active the relay switch,wired hundreds of lights this way and never had any issue.