This is awesome, thanks for putting it together! For me, I've had the most luck with HN fiction recommendations so I went there first. The distinction between "Literature & Fiction" vs "Science Fiction & Fantasy" seems to be a bit arbitrary. For example The Hobbit is in one category but LOTR is in the other, Neal Stephenson and Andy Weir are in both, etc. It might make sense to just merge all the fiction together. Plus that way you can short-circuit any debates about "is science fiction literature" :)

Edit: another little nit: it looks like quite a few books list audiobook narrators as coauthors