My only advice would be, if you are having the tubular building done ask the engineering department for structural hanging load analysis. Have a beefed up spot put in or at least have the load analysis for future.
With a hangar that big, you never know when someone will want to have a 180 hanging from the ceiling switching on/off floats. Would be nice to know what it can take.
We did this recently here and had to have a new analysis done. It's easier when they are willing to help and trying to sell the structure.