I am looking at building a multiple beacon bar. It is gonna be one-of-a-kind, so I can't see trying to buy an original used bar and making my beacons fit. I'm just going to build it from scratch. I am figuring about 47" long. How tall/deep should I go? Is there an advantage of using square stock over round? I am talking about a horizontal bar that will sit under separate beacons to keep them in a nice straight package, like was common in the 70's