@Chris - If it was trivial I would have offered a more reassuring response about me adding it than just suggesting the best workaround I could think of
I'm not saying "never" for retrieving a setting based on the selected book, but it adds a lot of complexity for a very niche usage and would be a lot of work. And it creates all sorts of other issues that have to be thought about. For instance lets say I allowed a user to associate a book tag with a named saved settings profile. So you setup a saved cover setting for "Science Fiction" and another for "Fantasy". What do you do if a book is tagged with both? What do you do if a book has neither - at the moment the plugin by default shows the last cover settings you used, but that might "confuse" users who become unsure as to whether the setting was chosen because it matched the book or it didn't match anything. And what do you do if the user selects a mix of books, since you can only edit/apply one setting at a time? It very quickly becomes convoluted and hence time consuming to design and implement.
Your request re editing the metadata in order to fit better does sound more generally useful, for those who are like you taking more care with what gets generated. However again it falls apart for users who have multiple books selected and I don't see an easy way around that beyond disabling the feature in that scenario.
The final suggestion re identifying books that have had a generated cover applied by setting a tag or custom column sounds a little "easier" to implement. I don't see many users utilising it, but I vaguely recall one other user asking how to identify such covers in the past.
Thanks for taking the time to post the detail of your requests.