I don't understand the question.
I don't understand the question.
The position of the shoulder at the bottom of the squat is not determined by a point on the femur. It is determined by lever lengths and bar over midfoot, knees above toes, hips lower than knees, bar on posterior deltoids, and spine in normal extension. Wherever the shoulders are when these criteria are met is where they should be. Bar above midfoot is the most important one.