The decision to end my reconstruction with narration (while a practical way to offer closure to the story due to the lack of visual material) was partly influenced by my love of Christopher Husted's essay of the "rising/falling" action of the 131 min. edit. Excerpted in the liner notes to the CD issue of the Herrmann's original score, Husted convincingly argued that the true climax of "Ambersons" is George slamming the door in Eugene's face, which surprisingly comes mid-way through the film. Husted goes on to suggest that Welles developed a series of scenes for the first half of the film which are "mirrored" in the second half after the unorthodox climax. An example would be the scene just prior to the "climax" where George unwraps the framed photograph of his father and the scene immediately after where Isabel comments to George about the framed photograph. Other examples would the two veranda scenes (in the first, Fanny dismisses the idea that automobiles will amount to anything; in the the second, she excitedly discusses investing in auto headlights with Jack), the two stairway scenes (in the first, Fanny eggs George on about confronting Eugene; in the second, she admonishes him for it) the two kitchen scenes, the two "George & Lucy walk/ride through town" scenes, etc.
These sequences are ordered in a way that scenes appearing near the beginning of the film are "mirrored" by scenes placed near the film's end. For example, the young George strikes Roger Bronson in the stomach very early on in the story and much later, after the "fall of the Ambersons", he goes to Bronson to ask him for a job. Note as well that George the college student tears through the streets in his carriage endangering the citizens who mock him; later he is struck down himself on the same streets and is unrecognized. At the same time, scenes appearing closer to Husted's "climax" will have their "paired" scenes in much closer proximity to each other (the aforementioned "framed photograph" and "stairway" scenes).
Where Welles broke with this model slightly was in not including closing narration (apart from the "read" credits). While he does reintroduce himself as the narrator just prior to Major Amberson's death (interestingly, the first line of audible dialogue heard after Welles' previous narrative passage introducing the "Last Ball" is "...I suppose that's where they'll lay the Major out when his time comes" spoken by Uncle John), Welles avoided "mirroring" his opening narration at the film's end.
Extending the Husted model of symmetry a bit, I chose a passage from Tarkington's novel which represented the exact opposite of the passages Welles chose to open the film. Since Welles honored the model throughout the rest of his adaptation, I didn't think this was an inappropriate addition.