On the model card question: you can push your model card to the model repo itself (that actually is not new, we’ve supported loading model cards from S3 for a while even if most users still push to the transformers repo)
See this model for instance: https://huggingface.co/Helsinki-NLP/opus-mt-en-de/blob/main/README.md 1
Then a specific version of the README.md lives on a branch (then you can push to branch v1 or fine-tune-experiment or whatever), or pinned at a specific tag (v1.0.1). Does this solve the use case you’re describing?