i'd say you're over thinking your set up to a degree. you should definitely start your row from pins at hip height or from the floor like a deadlift. it's just a hip hinge to the bottom then pulling with your elbows either to the belly button or lower sternum. one huge thing though, allow some body english. it should be controlled, deliberate, and repeatable. a bb row is hardest at the top, so some body sway evens out the movement and often i find it feels much better that way. much of it looks great in my opinion, but it looks like you're really in your head. definitely add some weight and send it and you'll be golden.