My RV solar system.

Almot wrote:
With series connection they would save on $$ J-box, so more expensive Tristar 45 and #10 MC4 wire would not increase the parts cost. In fact, without J-box and #4 wire there would've been less labor, though this doesn't necessarily mean lower labor costs ;).
What's important is that they would've got a better, more powerful system then.

The TriStar 45 and its TS-RM does not provide a complete battery monitoring function, so a TriMetric TM-2025RV or ME-BMK would likely add to the cost. Series connection provides the risk of power loss with intermittent shading. Woulda, Coulda, Shoulda. I evaluated my options based on my expected use and this is what I came up with. Sure things could have been differently, but they weren't. It will be up to someone else venturing new to learn from your comments as I'm likely to die with what I have in hand now.