We don't run experiments on a single page, but instead run them across groups of similar pages. The easiest way to think about this is running a test across a "product" template on an e-commerce site. A site could have thousands of product pages, but they're all on the same template. We would grab a set of a few thousand product pages, and split them into control and variant groups, execute the change on the variant group, and monitor how Google reacts to the groups in aggregate over a period of time.

Depending on how many pages you have, we can run many tests in parallel.