I thought about that when I was reading those pages. It may not be easy to determine the exact head positions needed from some of the online diagrams, but there are Youtube videos that show it better.

Shows the Epley procedure, along with an animation of how it repositions the crystals in the ear:
https://www.youtube.com/watch?v=9SLm76jQg3g

Another procedure called the half-somersault:
https://www.youtube.com/watch?v=mQR6b7CAiqk