I think your observations are pretty much right, and there isn't too much more to add. Maybe a tiny bit of bent arms when you set-up, so either narrow your stance or widen your grip a tad to get perfectly straight arms when you set up your pull. Do you have long tibias relative to your femurs? It looks like you do but I can't tell for sure. You have a somewhat unusual looking set-up, but that would account for it, I think.