From the moment she strode through the red-curtained archway of Diana Vreeland's Manhattan residence, Deborah Persoff exuded an ebullience that one typically senses only from established performers appearing in test-marketed star vehicles. Suffused with a regal pride that verged on but never became haughtiness, Persoff cut a commanding figure in Full Gallop while spouting the legendary Vogue editor's slew of pithy fashion statements. Despite the inherent weaknesses in Mark Hampton and Mary Louise Wilson's script, or perhaps because of them, Persoff and director Chip Walton complemented each other's strengths to offer up an engaging evening of style, whimsy and steely sophistication. And as Persoff moved about the stage with near-balletic flair, it became clear that her mother's belief that Diana lacked natural beauty was, on the whole, a monumentally superficial observation.