Juju Openstack Bundle Deployment Question

Hello everyone, i have been testing the Juju flavor of openstack for the company i am working for, and so far we have been loving it, the system works as advertised and the learning curve is not as steep as others. However i have only set up individual charms so far, in order to familiarise myself with the charms way of doing things, however i am aware that the intended way would be to perform a deployment using the bundle. In that regard i just have one question. As we have a few things we want to modify (Using vxlan in neutron, and adding the necessary settings nova needs to use ceph) which are configured via .yaml files, my question is for the bundle deployment do those go in as variables inside the ./stable/openstack-base/bundle.yaml or is neutron for instance configured in a separate bundle and then called on the command line when deploying i.e juju deploy ./bundle.yaml --overlay ./openstack-base-spaces-overlay.yaml --overlay ./neutron.yaml ?

If you intend to work with the official bundle and just override some settings, then overlay is the way to go.

That is exactly what i wanted to do. I assumed that it was the overlay, but was not 100% sure. Thank you.