Chris, John Engs says the squarewall tube has more laterial strength so that's why they used it. This stuff is 3/8" thick, so it isn't going anywhere. One of the problems is that they have to drill A LOT of holes in it to connect up the coupler pocket and that is taking lots of time because they only have
ONE magnetic drill. Does anyone have a good used one, or care to donate to buy a new one?