Just a note: I did not actually get around to changing the Quill micropub request. I only updated the microformats on some read posts. I will do it manually for a little bit longer just to see if any other issues pop up, then I will add it to Quill.
For the p-read-status, what do you think about these machine-readable values to start: to-read, reading, finished? want-to-read seems verbose to me for a machine-readable value.