A detail on the original structure I really think stands out: The vertical opening (maybe 18" to 24" tall?) held in place by the slat-rotating pin on the right (and I therefore assume is hinged on the left, but on the other side. Given that the other three hinges just above are visible out front.
I built a structure 30-odd years back which had a similar remnant of a door (using a stone sill) above what was later a wider garage door--incorporating a wider stone sill). Hoping to find someone who can tell me where I found the plans for it, but I still can't find it.
But this kind of thing you are doing here is part of why we even scratchbuild structures like this one in the first place, right? Because they are all ones of a kind.
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Like the others here, I look forward to seeing the rest. Go, man, go!