Yes Alan, in a perfect world you would put the subwoofers exactly where they would sound the best, along with the tower LCR speakers and they would be as large as you need and budget would also be no consideration. But aesthetic considerations are often very important in home theaters, especially rooms that are multi-use and have to consider furniture arrangements and my 5 little kids and their friends knocking speakers over and climbing on subwoofers like they are a playground toy...You don't tell the subwoofer where to go, it tells you.
Having predetermined locations in your theater for subwoofers is a bad idea. You need placement flexibility after the subs are in the room if you are at all concerned with maximizing performance. If your room is rectangular and sealed, the REW Room Simulator will give you a good idea of whether or not your proposed locations will work well.
