There's no need to splice and dice, there are already six wires bundled up on the firewall over the glovebox (passenger side, in the hood). There are two bundles of six truncated wires: one bundle goes the auxiliary (overhead) switches; and, the second bundle goes (pass through) to the passenger footwell (fusebox). I'd tell you which one is live - for me, it was on the left as you look from the front of the truck towards the passenger compartment - but Ford doesn't seem to know since it recently sent a warranty/recall/update that was wrong (I hate it when I think I'm wrong but I wasn't). These wires are rated at 5A, 5A, 10A, 10A, 15A and 15A (based on their gauge and the parallel bundle going to the overhead switches).
