Install new Item DocType to ERPNext App or to new Module?

We are adding new master and child DocTypes which are largely based on Stock Items (and child tables). Best practice; should we have these installed to the ERPNext Stock Module or to our new Web-to-Print Module? It would seem users would want to set-up, configure and maintain all Item DocTypes in one module?

You can add them in the stock module in your config/ - just add a new dict “Stock” module and they will show up under stock.