I am getting ready to install a new basketball post. I need to dig a hole at least 3 1/2 feet deep and about 18" in diameter for the post's footing. The instruction manual indicates that using one of those giant tubes (sonotube) is optional. My question is this, should I just dig the hole and put the concrete and footing directly into the ground or should I use one of those cardboard tubes, pour the concrete in the tube and then put the footing in? I can't figure out what the difference(s) would be. Any thoughts would be appreciated.