I like the mirror idea, it's pretty elegant in design, takes no additional square footage by making use of the vertical space, increases output and could shelter the panels at the push of a button. Would it still require additional panel spacing though to avoid the mirrors shadowing each other?
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Tandem Solar. I had looked at Renvu as well but at the time I purchased all of my stuff Tandem Solar had better pricing. If you know what size system you're going for and can figure out which panels and inverters you want they make it pretty easy. You can give them a call and they can punch it all in their system and put a quote together of everything you'll need. It helps to know how many panels and rows you're going for and if you want them in landscape or portrait. I think they're used to dealing with installers though, so the one downside is that my racking came with no instructions whatsoever. It was easy enough to look up the PDF on the manufacturer's website however for instructions and torque specs.