I have noticed that some folks like to draw a straight line form the ball to the nose to disprove a steady head- that it moves to the side. In my neck of the woods- photography- thats a MONOPOD.
Homer talked of a TRIPOD. The lines would be drawn from the foundation- the feet, both of them - to the eyes. Head stays centered on a tripod.
And any lines drawn to reference Stance Width -- or "between the feet" -- should be from heel-to-heel. Likewise, any 'uphill-downhill' camera 'skew' must be adjusted so that the golfer's Stance is level (horizontal).
Like this:
This correct approach enables the student to separate immediately fact from fantasy.