So when I experiment with modifying a Rhino surface referenced by Grasshopper, I’d like GH to be notified if the surface has been modified. In the current case when CVs/“grips” are modified. But how can I in the easiest way make a GH component be aware of the modification?
Not quite sure what you mean here? When you edit a referenced Rhino object, GH updates all components downstream of the referencing component automatically. So in effect, GH is notified of any changes to the Rhino surface.