Also as for the switch you shouldn't need one. The harness has a trigger wire which you will wire directly to the upfitter wire under your hood. Then you'll run both positives to the battery and ground the two negative wires on the truck. I wouldn't ground the negatives on the battery. LP9 have a high and low beam so if you want that functionality you'll need to wire the high beam and low beam trigger wires to different switches.
So I wrote another thread but it seems as though Baja designs has pretty liberal overages for their amperage ratings. I installed a 20” ONx6+ that’s rated and 16.8 amps and draws in real time 10.8. Some of these relays and non sense are over kill.
Did you actually read what I wrote? A 10 amp load will never blow a 15 amp fuse unless you short to ground. I mean I build first responder vehicles for living. I know a little about what I am talking about. Amp clamp your lights!!