That will not give him the angle that he needs, think we have been down this road a few times.That is very ingenious. However, I would just suggest that you set your saw at 22.5 deg.
Put a scrap board on your saw and set your saw to 22.5 deg. Saw the board in two. You will now have two boards. Each will have one angle that is 22.5 deg and one that is 67.5 degree.