This has been my approach (together with CiviCoop) to load test a big site with CiviCRM where most visitors where expected to login.
Let me know if you would agree with this approach or if you have a better alternative.
Now that Drupal 8 has built-in support for Web Services, you’re likely thinking about exposing the content in your site with an API. But should you make the data available in JSON, XML, or both?