Im not sure you're ever going to find a book on Orthochirus but I do have the 2004 Kovarik paper which is a pretty comprehensive revision and taxonomic breakdown of the genera. I also have the Fet paper regarding Orthochirus metasoma as an evolving sensory organ which is much shorter (!!) and an interesting little read.
This may not be what you're after and in this case I do have a short caresheet written by a friend which I may already have sent you??
Hope these are enough to quench your interest for the time being. Just PM me if you want any of the above.