Post-Caustic Esophageal Stricture (Bougie Dilation)

A 24-year-old man presents 8 weeks after deliberate ingestion of drain cleaner (strong alkali) with progressive dysphagia to solids and liquids, weight loss of 9 kg, and one episode of food-bolus impaction. Barium swallow demonstrates a long (6-cm), narrow (4-mm) tubular stricture of the mid and lower esophagus with smooth, fibrotic appearance and proximal esophageal dilatation. Endoscopy confirms a tight fibrotic stricture without active inflammation or ulceration. The structure marked **B** in the diagram represents this post-caustic cicatricial stricture. Which of the following best describes the PREFERRED DILATION TECHNIQUE and the SAFETY PRINCIPLE that should guide this patient's management?