It's been eight years and I am still waiting for a reply!!!
But also, what about changes in the lady's head during the Viennese Waltz?
Shouldn't the answer be obvious? Each partner's head is were it needs to
be to achieve the desired movement, in terms of travel, turn, smoothness,
stability, effort, inter-partner force, athleticism, dizziness, etc.. The head
position is reflected in and compensated by the rest of the body, as well as
the body of the partner. Nobody ever asks a driver where his/her hand or
foot is when making a left turn, because there are too many factors to
consider, including the capabilities and characteristics of the car, the
road condition, etc.; the hands or feet are where they need to be to
negotiate the turn.
Within the above context, since step 4 is the backing step in a Natural
turn, that's when a dancer would be roughly looking back LOD. By
step 5, the head would be looking roughly back diagonal center. I
believe that's the case here...
youtube watch?v=YcaYFLeKwJA