I promise you'll have an easier time if you use a non white background.
The shading itself is solid enough except the fact that monochrome is boring. perhaps a shift towards a nice desaturated blue on the darker hues...it should stillread as white. If you're going for a more bonelike appearance, i'd go with a soft mustard color for them
Also, I ought point out the 'modify' button. double posting all the time is generally frowned upon unless your thread has fallen off the first page.