Very nice. Love the detailed write up. It's timely too. Been looking, because I'm in a rate tier state and it is impossible for this (small) house to stay in Lifeline. Most of mine is above $.09 some is <gulp> $.31 I go over into the highest tier also.
I glanced at a Solar kit in Frys Electronics. Big money for small watts. This makes more sense.
Oh, and wire is pretty simple. Bigger (fatter) wire for higher currents and longer runs.
12 guage is house wiring for 15-20A @ 115v. Goes back to your panel, so that's the standard for current and distance. Wire is bigger or smaller from there, is how I look at it. For example, I'm running a sub-panel to the garage. That will take 8 guage because the breaker will be 50A. The cables in the battery bank are fatter than the wires from
the solar panel. Like that.