Hi --
With over 8 years of experience in Web Design, SEO, and WordPress, I can provide you with an optimum, great looking, functional, website for your purposes.
I've thoroughly reviewed your website selection and my recommendation is, only if you a selling very few books, Flatbook Demo 1. The reason being the others would be too distracting from the books themselves. Honestly, I don't think Flatbook Demo 1 is a good choice either. This situation needs a cleaner, clearer showcase for your books, and I believe you would be more satisfied with another choice for a website in the long run.
I would find another theme, or if you would like to hire me, I would be happy to do so for you, you making the final selection of course, after you supply me with a little more information, such as what kind of volume you'll be doing, which is critical to your ultimate choice.
Also, as a service to my clients, I provide SEO built right into the back end of your WordPress site, after extensive research in your particular niche.
I haven't bid on Freelancer until very recently, but have a 5 star rating on Elance.
Thank you,
Kathleen Johnson
Profile & Portfolio: https://www.freelancer.com/u/WordPressExp.html