Ah, sweet updates!
Nice edit rikfuzz, though with her left breast slightly lower than her right seems out of sync with the orientation of her arms (raised arm should shift the pectoral and pull the breast up?)
But by all means yes, the breasts look more in perspective with an under-side!
Issues I recognise:
The main thing is the plumb line from the top of the head. Compare various landmarks of the legs against it, and you can see what I mean about the figure appearing off-balance. Its like the entire legs and pelvis need to the grabbed and rotated clockwise.
Regarding the neck, I hope it's obvious what I'm trying to say. The silhouette is basically correct, but the rendering has introduced all manner of strange impressions. Break the area down into planes.
With the head, you can draw lines from the corners of the brows to eachother, and to the ears, and you get a rough "box" of the head, which lets you measure the implied perspective/orientation of the skull. You seem to have almost done an oblique projection, with the face dominated by horizontal and vertical lines, and then the other parts of the head extruding back from it. Jawline should angle up from the chin, and curve upwards in line with a horizontal at the mouth. Let me word it another way: jaw curves up where the mouth is. Yours seems to almost be flat, and then curves up near the vertical of the brow.
Last thing is just something that could be a concern; different stages of rendering across the piece. I recommend working iteratively; at any point you should be able to say "if I stop now, the piece would function". Work in progressive refinement of detail. Begin with basic blocks of light and shadow, and refine the planes in finer detail until you're satisfied its complete. This isn't the only way to work (I don't follow this so vehemently, but hold it as the ideal), of course, I just see a potential problem with how you're proceeding currently. Seems like you're beginning from a shadow silhouette and adding increasingly brighter shades until you reach the speculars. Can creep into pillow-shadiness.
Pretty sure the far arm's proportionate. The speculars don't look pillowy do they? 
Forearm appears too short. I'd say speculars on their own, cannot look pillowy. It's the combination of all the shades and how they are arranged that decides pillowness (oh god, I used that as a noun?!). The speculars actually beg the question "wheres the lightsource?" because the speculars on the upper torso imply up and to the left towards us, but the shading on the head implies slightly up, slightly to the right and slightly towards us.
