I don't remember who said it, but the idea of standing on the balls of the feet causing the calf to flex, what happens if this is the case is that you are puching the balls of the feet down, and away from the shins. What needs to happen is that the shin should press into the boot in order to weight on the ball of the foot without forcing it (its a relaxed stance on the balls of the feet).
Now in terms of getting the shoulders forward in a balanced stance, the idea of the toes, knees, shoulders in line has basically been brought up many times, but if we align our body this way when standing static, the pole needs to be vertical. However, as we begin to move, it is like balancing a pole in your hand and moving forward, there needs to be a counter movement (in this case, as we move forward, the pole needs to tip forward so as to not fall back). When we ski, as we accellerate, we need to tip this focal point (toes, knees, shoulders) to compensate for out forward movement on the skis.
The best way, in my opinion, to really feel the whole body moving forward in this way, learn to drop into a half-pipe, and not letting the skis run away. Often times after getting this feeling, you'll probably be more able to keep the shoulders (but more importantly, the toes, knees, and shoulders) forward when in steeper terrain and bumps.
However, I would never understate the importance to go back and ski your turns as slowly as possible to make sure all your movements are dialed in.