I'm experiencing the new unity plugin with Arkit 2.0 https://blogs.unity3d.com/es/2018/06/14/whats-new-in-unity-arkit-plugin-for-arkit-2/ Where is the example of scaling content? Do I have to update me from Git the branche containing it? Can't you make it in the root? Regards!
In case you haven't found it yet check out the following branch. it was made in an older version of unity and the ArKit has been updated since this branch was made but you should be you can make minor changes to make it work even in Unity 2018.3. It uses a two camera setup to produce the scaling effect. scaled-content-test