The RV shed is one of the standard sizes for Eagle Carports, although they can provide custom dimensions.
The one I had installed is 31 feet long by 18 feet wide. I think the base is 1 foot shorter in both length and width which allows for 6" overhang at the roof level.
With 18 foot width, I can leave my slide out in the open position. The awning only has a couple of feet to unroll so I leave it rolled up.
Even though the Heartland Wilderness 2175RB specification is 11' 9" height, the RV shed height of 10 feet is sufficient, as long as you don't specify end panels.