@MrWolf_UKAfter this request, I checked the library and found that the 'rating' field is used only in 0.78% of bookmarks. So woefully under-utilized. Second, I compared the bookmarks that do have a rating with their corresponding votes (if any) and found that nearly 90% have identical values.
So, a separate 'rating' field in the library is practically useless.
I've updated the system to update the rating column in the library whenever one casts/changes their vote for a story that they have bookmarked. I also copied the voting data into the rating field.
That should allow you to sort your library by rating. You can also use the advanced search page to find all the stories in your library that you have voted for and sort the results by the stories score. Unless your vote is too different from the story's score, it should allow you to find what you want.