Hi @mjohnston - you can use your own domain/storage instead of raintank if you have server-level access to edit the configuration file. Our documentation has instructions for storage providers that are S3 compatible - https://grafana.com/docs/grafana/latest/administration/configuration/#external_image_storages3
For making dashboards public you need to authenticate anonymous viewers: https://grafana.com/docs/grafana/latest/auth/overview/#anonymous-authentication
There’s also another permission to deny edit permissions to viewers here: