Excellent presentation!
Did you look at any spatial customizations to the FretBoardGraphic to make the orientation obvious? I thought of having the low E string be a bit thicker, the middle strings be middling, and the high e string be a bit thinner. This would be completely unnecessary for experienced musicians, but newbies wouldn't have that instant recognition. A few years ago, Skeuomorphs were used in iOS design elements; they make the design look a bit friendlier and more organic. That might be a nice thing to try here.
