All my channels are assigned based on what controller I am connecting a particular display element to. Layout does not care what the channels are. My first controller is sitting on my front porch and connects to everything that is hanging on the house so that is where I start. I start with gutters and number them sequentially even though I have 4 gutter models, G1 is on the left side of the house and G4 is on the right end of the house, then I also have a group called Gutters which includes all 4 gutters. It is all up to you.