I actually love this image, mate. My only "negative" (if it can be called that) is that the piano and lighting drew my eyes away from the model because they were so naturally "alive" while she is so very pale. Given how beautiful that she is, in my opinion that speaks volumes for the setting you both selected for this shot. Great work, as always.
ok now that i look at the pic again i can see the back is fairly thick where she's perched. the upright grand piano at my moms house isn't that thick. if you flip the top open the back is maybe 1½ or 2 inches thick tops, with the big metal frame holding the bass strings bolted to it.