Chris,
I've spent some time with speed fliers, even flown a couple of my own, and the only place to position a single bladed prop is so that it is upright when the engine stops.
The reason for this is practical rather than theoretical, it's so the prop won't break on landing.
End of story.
I can't think of any one of the previously mentioned speed fliers who would not go to any length to ensure the prop was totally balanced. Apart from them being very strong on attention to detail, I would think that they would want to remove one possible source of vibration from an admittedly unbalanced basic unit.
Unless the article was written by someone like Pete Halman, I wouldn't take that part of it too seriously. Other parts of the story may have merit.
Come flying soon Chris?