Once you have installed the door stopper, open the door to 90 degrees. If the wedge does not stop the same, then you need to choose a wider wedge. All this also depends on the type of door and hinge. You might need expert help to understand what would work for your door. You may also need to slide the wedge slightly under the edge of the door to get the work done effectively. Try on various ones until you get the right angle that works.
Your door wedge is an important element of your home improvement needs as it helps control the door from swinging too much and acts as an alarm to help you understand that the door has been opened.