Sadly, there's no solid documentation yet, I'm currently working on it though! An upgrade guide is a great idea to include with the docs. I'll look into that.
In the meantime, if you save your changes to the Feedback object as a separate prefab, then update the asset, your changes will persist. Just double check that you're not missing anything on the included Feedback prefab.
Edit: Documentation can be found here, and is also included as a PDF with the asset :)