Did the adjutant ever come down to the balcony or just stay up there when you visited? Based on the doorway and height of the railing it looks to be about the same size as a large Yellow-Billed Stork.
@Sarus Crane he stayed on top of the entrance for the entirety of my time at the zoo. You were still able to get super close which was really a wonderful experience, if a bit intimidating. When I was exiting and walked under where he was standing in the photo, he glared down and began trying to peck at me through the frame.
They are perhaps just slightly smaller than an adult yellow-billed stork.