I've been reading Doctor's Orders and it is indeed quite good, both as a novel and as a McCoy story. Dreams of the Raven I quite liked. Those are the two really McCoy-centric novels I would recommend.
Shadows on the Sun is a bit of a downer, if you hadn't guessed from the title, but also very focused on McCoy. The Better Man was . . . okay, from what I remember. Bloodthirst is pretty good. The Romulan Way is quite good. I was a bit put off by the love interest factor in Covenant of the Crown, but otherwise I think it was fine. Spock's World just has McCoy delivering a speech, and that's really about it for him IIRC.