Whygimf, I generally like to strive for efficiency, and economy of movement and effort when I free ski.
Typically when free skiing I strive to maintain a stance that incorporates efficient, through the foot balance. By that I mean that I try to remain fore/aft neutral, not leveraging against the front or back of the boot cuff. As soon as one starts to leverage against the boot they make that portion of their boot part of their balance platform, which serves to degrade foot feel and balance, and requires greater recruitment of muscle involvement to remain dynamically balanced.
Simultaneously, I focus on maintaining rotational alignment during the turn (feet, hips, shoulders on the same rotational plane), which lends to maintaining similar fore/aft balance neutrality in both feet. When I make my release move at the end of the turn, pressure transfers to my old inside foot/ski, and my CM is set in motion across my skis. My rotational alignment allows the pressure to immediately transfer to a fore/aft neutral state of balance on my old inside foot/ski.
The new sidecuts allow the skis to be operated very effectively in this consistent fore/aft neutral manner. Generally, when free skiing, modifying edge angle is all that's needed, and all I use, to produce the desired turn shape. Seldom do I find a need to supplement my turns with fore/aft balance alterations, and suffer the resultant balance inefficiencies.
When I do feel a call to do so, it's normally from a desire/need to crank up the intensity of the top of my turn, and I accomplish it with a fore balance shift that leverages the front of my boot. It hyper engages the front of my ski at the top of the turn, and thereby sharpen that portion of my turn. I can hold fore position throughout the entirety of the turn, if needed, or I can return to fore/aft neutral later in the turn if my turn shape mission has been accomplished.
Other times, I'll move to an aft balance state through the bottom portion of a turn. This can provide a stronger forward energy release, when speed is an issue (see Ligety and Bode), and it can also contribute to a quicker cross under transition when quickness is an issue.
Sometimes too I'll alter my fore/aft balance platform in various ways, not out of need, but just to keep sharp my abilities to perform outside of ideal/efficient states.