mebe007, I just went out to my shop and measured the hole in my factory carpet (I have a manual trans). Mine isn't cut square. Running parallel to the drive shaft and facing the dashboard, the left cut is 6" long and the right cut is 7 1/2" long. The back cut (towards the rear) is 5" long and the front cut (towards the dash) is 4 1/2" long. If you can borrow a hand held steamer (for spot cleaning carpet, etc.) it will help you form fit the carpet around the hump! You should try to form fit the carpet BEFORE you start cutting the hole! Always start by cutting a smaller hole and then enlarge the hole a little at a time so you have enough carpet that the stainless shifter boot hold down piece screws will go through the carpet. ...Good luck!
Doug