I'd prefer a full event inside the tag. Bringing NIP-94 tags to kind one can be messy.
It can be as simple as:
['r', 'url', 'nip94 event']
Otherwise, it will be a little messy to rebuild the object.
['r', 'url1', 'hash', '...']
['r', 'url1', 'descriptor', '...']
['r', 'url2', 'hash', '...']
['r', 'url2', 'descriptor', '...']
Also, I am not sure how well relay indexes will deal with this.