I thought of something else about that bracket. If the umbrella is in a bracket on the side of your tear, half of the umbrella is not over your galley, it is hanging outboard of the trailer. What's more, as the sun moves across the sky, the shade will wander away. For this reason, I think there should be two brackets. One on each side of the galley. Then you can choose the bracket that works best for any particular time of day.
I'm thinking about galley extension tables that will mount in several different locations. Perhaps they could use the "outboard" shade.
Really, the best reason for using this type of umbrella is that it would look "retro". I'm not sure if the awkwardness of dealing with its size, weight, position and vulnerability to wind would offset the look.
Thanks for your replys. Are there any others that have tried umbrellas?