Disclosed are methods of and systems for depositing a film. The methods may include: (a) determining process conditions, including a flow condition of a curtain gas that flows around the periphery of each station in the chamber, for performing film deposition in the chamber, (b) flowing the curtain gas to each station in the chamber during film deposition according to the process conditions determined in (a), (c) determining, during or after (b), an adjusted flow condition of the curtain gas in the chamber to improve substrate nonuniformity, and (d) flowing, after (c), the curtain gas during film deposition according to the adjusted flow condition determined in (c). The systems may include a gas delivery system, a processing chamber, and a controller having control logic for performing one or more of (a)-(d).