Click this link for more online lessons. The actual 7 position is made between the arm and shoulder, I am demonstrating how to use the club shaft in a similar way. The number 7 position is between the shoulder line and the upper left arm for right handed players,it is not the angle between the leading arm (your left) and the club shaft.
Quick note from Dan Shauger
Although the angle you speak of in the videos will remain very close to what you are showing we are not holding that angle, it opens slightly before we get to the ball as the power arm extends at the elbow.
However we do arrive at the ball with the throwing wrist back. This creates the forward leaning shaft and the hands ahead of the ball position at impact.
Having said that we do not physically hold the the throwing wrist back, rather it is held back by the weight of the club as the pivot accelerates the club endwise toward the ball,
We simply allow the club to follow the arms down and out and allow the hands to react to centrifugal force and gravity and release fully through the ball.
At first when your players learn this the throwing wrist should be held back and the entire arm and shoulder "package" held exactly as it is at the top of the swing all the way to the ball.
The power arm should be allowed to naturally extend as the package returns to the ball with both the wrists relaxed at impact to allow the late arriving club head to swing.
Number 7 position in golf swing