As the lead developer responsible for a financial risk calculation API hosted on Cloud Run with a gRPC interface, you continuously work on enhancing the risk analysis features. You want to make these optimizations available first to a select group of customers who signed up to test the improvements before releasing them more broadly. Your CI/CD pipeline has created a new version of the API as a container image, which is now stored in the Artifact Registry. Which rollout strategy should you use to manage this controlled release?