Of course I was Andre,
I don't shoot enough, far less use negative space myself, so I looked at a
few of Donald's shots - he does usually have some kind of shading of the sky happening.
We had a member back in 2008/9 that was a master of negative space, but he's no longer active and I don't have time to try to find any examples of his right now. We risk hijacking your thread of course!
Thinking on it some more, I might also suggest that negative space should occupy 60% or more of the image area. There's
another statement to guarantee someone disputes it.