@fu_man I think keeping gate width and shoulder direction is a fallacy. As noted earlier in the thread, I got exactly the opposite advice from Rossi, and it fixed my width, fixed my balance, fixed my gate load issues all at the same time.
Said differently, ONLY if you are so immobile that the direction of your shoulders causes your ski to turn inward, should this imact your width.
Conversely, suppose I put my shoulders square to the ski tip in the glide. All else equal, I could argue that posture will pull you narrow (if you don't carry enough speed to stay wide). Staying wide is a function of your speed vs. the boat, not the position of your shoulders.
When I point my chest to the pylon I get wider, and stay wider, with no pull from the boat dragging me back in. Why? Because I carry more speed and am riding on the front of my ski.
Try something. Stand in your living room feet side by side, shoulders back. Your weight will be in your heels, particularly if you are holding weight (like dumbbells), which emulates the load of the line. Now keep the dumbbells and put your left shoulder slightly ahead of yourself and leave your right shoulder in place (because in skiing your right shoulder won't go behind you due to the pull of the boat). Now your weight will be in the balls of your feet.
I believe that for the average skier, like me, all of the advice about flex this, bend that, etc, to try to get weight on the front of the ski is too complicated and it isn't my natural body posture, thus making it diffficult to replicate or maintain. However, if all I do is think about where my chest is pointing (at the pylon on pull out and glide, then quarter way toward the boat (rather than directly in direction of travel) the rest of the time, weight distribution takes care of itself. Simpler is better for me. So, rather than tell you to flex your ankle, bend your knees, get your hips up, etc, I'm going to say stand like you would on solid ground, and let your shoulders "slightly" toward the boat. All those other problems go away.