Hey, I like boob grazing as much as the next guy!
My problem is the angle it forces my arm into ... puts tension on elbow, torques wrist ... not a problem for short forays across, but for extended periods ... not nice.
Right...and that's my problem with this etude. Even though it's not arm-crossing, it moves back and forth quickly over the whole length of the keyboard, both hands moving parallel to each other. I couldn't make it through the first section sitting as close as I usually do. I feel like it causes extra strain on my back and neck, too, because I'm short. My keyboard in my room is set a good few inches higher than the pianos over at the school, and I can get comfortable there, but it's awkward going from that to one of the school pianos.
So, sitting as far back as I do, I'm sort of hunched over the keyboard, so it's like I have to move farther to cover five octaves than I would at normal position. Back and forth, back and forth...no matter how well I can stay relaxed through it, it still puts strain on a lot of things.