In order to ensure the best scenario for maintaining the coronal plane balance we need to take into account such subconscious-friendly measures as diagonal stance. However, we can go one step further in making the whole issue even easier - we must find the way the head moves simultaneously with the rest of the body and get rid of any independent movements that would make impossible to react to couterbalance in such rapid a motion as golf swing is. We all know a famous false myth of stationary head. Golfers trying to achieve it make a lot of goofy efforts making it impossible to let the head move naturally.
Nature brings best solutions, as usually. Head is linked to the rest of the body via cervical part of the spine that is being characterized by a relatively large movability that, in consequence, ensures head movements, such as flexion, extension, lateral bend or rotation.
The most natural and physic-friendly position (because of gravity) of the golfer's head is forward bending, i.e. cervical spine in flexion. Not coincidentally, it is also the best natural position of the head to work together with the rest of the body completelly naturally on the subconscious mind level. Of course we talk about a not forced flexion.