Adding an alias graph to the default model

Hi I can create alias graphs ok - but I also want to manage the model/schema for my environment in a controlled fashion - so I want to be able to add or delete a reference to an alias graph for my collection of models to the default schema, (AFAICT thats the only way to get Explorer to find and use my model without user intervention- correct me if I'm wrong)

Is there a named graph for the default aliases I can add alias information to or any other way to implement this via the HTTP API? Does the default model use the same underlying alias mechanism?

Its not clear how models are added to the default schema either - but i suspect that might be documented somewhere.

I need to do this because I expect to have many hundreds of models and manual management is not feasible, nor will these be static enough to use as archetypes.

If I have some collections that are stable enough to use as archetypes would there be an issue if the same model is provided by the user and present in an archetype?