First, it is way too short. You can place it on your shoulder with comfort, but you cannot move it then even for 5 millimetres without lost of comfort. My T-shirt size is between L and XL so this is not the issue, the issue is exactly the length of the padding.
Second, you can think that you can move the strap inside the padding to place the guitar to the position you want right at the moment - anyway, you have just seen the padding falling down along the strap under it's weight when the strap was off... no way. It is impossible to move the strap when it is on the shoulder. So you must leverage the padding on the strap before putting the guitar on and starting to play and must keep the guitar in the same position all the way while you are playing. Wooden guitarist. Well, you can try to do all these tricks like sending the neck to the sky and picking on the level of your eyes - but there is the risk that the strap and the padding will move on your shoulder and one against another, and when you will return to normal... fail. You will be dreaming of stop playing and deal with discomfort before.
Very strange item.