If you look in the last part of that thread, I believe it has James Hirschfield showing the closed stance. Why? Because the ball position off the left toe can lead to a fade; if you want to offset the fade, close slightly. But I'd probably lay off the closed stance until you get the fade and either decide to keep it, or close the feet and compare.
And when you address the ball, a common error is for the hips and shoulders to still remain open even with a square stance -- so square up hips and shoulders (by closing them to a square position).