Coach Controls Wiring Harness?

I have also been stewing over rewiring my 70 Duster. I like the idea of the relays being there all on the fuse panel but still think they should be close to what ever they are controlling. I`m going to go with the EZ wire 21 harness and then get hold of crackedback for some relay kits that he has. Not sure if relays will be needed for headlights and such after rewire.