Private Spaces
We currently don't provide official support for Heroku Private Spaces.
There is a good chance that worker-based auto-scaling will work because it doesn't rely on any of Heroku's systems other than their formation API, which, from what we understand, is compatible with both the Common Runtime and Private Spaces.
To our knowledge the Logplex system in Private Spaces works differently from the Common Runtime's Logplex and therefore is less likely to work (we currently cannot confirm nor deny whether this is the case).
More information on this in the future.