Expand on model loading docs, make tags_csv optional
Is your feature request related to a problem? Please describe.
The UX for loading a model isn't very clear atm.
Describe the solution you'd like
Clarify docs and make tags_csv optional for models without hparams object.
Describe alternatives you've considered
A clear and concise description of any alternative solutions or features you've considered.
Additional context
Brought up by an issue