I flip my space bar; I have smaller than average hands, but definitely not teeny. My right thumb, the only one to hit the bar, hits it below the "N," all the way to the right. Not quite in between "N" and "M," but definitely not the center of "N."
I did notice the other day that, as I was typing on my SSK, there was a certain angle I had my thumb for some reason (I forget what I was typing), and the way my thumb it the bar it was as if it were angled. I think my right hand was above home row or something.