Julien,
That seems to be a pretty sensible approach. I think we (the core developers) are trying to figure out the best way to support these types of changes through depletion. Both for geometry and possibly material edits. There isn’t a great timeline at this point, but please let us know how your experience goes! Any insight would be great as we sort through this.
With respect to extracting the depleted material compositions, we don’t have a straight forward way for doing this. Yet! There are two active and similar pull requests that are angling to add this functionality. Could be a good inspiration point for your own work.
Regards,
Andrew