The OP's panels couldn't be better looking as far as neatness goes.
I know that you need some ty-raps here and there, but I don't like any more than is absolutely necessary. It does seem that there would have to be some sort of heat retention in the center of that bundle, and I just don't see any reason it needs to be that neat.
Back when I was working for a contractor in a factory, I thought the local electricians didn't know anything, putting boxes everywhere.
Having moved to the other side of the factory wall, I know that I will be much happier if you install lots of j- boxes, long wires, and few ty-raps, because I'm gonna have to trace stuff, take amp readings, and move stuff around constantly.
I am sure the facility in which the stuff is installed makes a difference, but I think one should, whenever possible, leave generously more than enough length of wire than is necessary to hook up . You can route it so that it looks nice... and always try to leave some place to put a clamp-on ampmeter.
Once the lid is on, they're all gonna look the same.:smile: