Hi @ernstch,
The dask example project is achieving something similar by providing a JupyterLab workspace: https://github.com/dask/dask-examples/blob/d7a69122d9c1c24f6583e7d46cd089cf1eb70ae8/binder/jupyterlab-workspace.json
The layout is then automatically loaded when the server is started on mybinder.org
For resetting the layout maybe a link to reset the workspace could work?
https://jupyterlab.readthedocs.io/en/stable/user/urls.html#resetting-a-workspace