material overrides on instanceable prims?

[sharktacos]

Using the Alab I'm finding that I cannot edit the materials on a asset which all live under instancable prims. I get the error:

"authoring to an instance proxy is not allowed."

My expectation is that it should be possible to create an override for the material using an inherit arc, but I'm not sure how to do that in Maya, and it does not automatically happen when I edit a material in the Attribute Editor. Is there a recommended workflow (other than not using instancing)?

From the Asset Structure Guidelines:

"Inherits and Classes

Inheriting from class prims is a way to set up USD assets for flexibility down the road. There are a lot of ways that inherits can be used to build powerful assets in USD, but it is recommended that models inherit from just one to start. Examples of edits made via inherit arcs could be variant selections, material overrides, or even new primitives. Broadcasting overrides via inherits is one way to make changes to scene graph instances."

and

"To materialize instances, particularly in larger assembly, the inherited class prims can broadcast material bindings to the relevant models."

I'm specifically wanting to do a material override on the inherited class of the instanced prim. Is this currently supported in Maya USD?