I had a similar problem with duplicate content issues on my WP blog. Now I try to use only one category for my posts and robot txt file to stop the G bot from indexing and caching my some of my pages.

I think that I might have overdone the robot txt file with restricting the G bot from too many areas of the blog.

I will have to try the category visibility-RH plug-in. Hopefully, it is fairly easy to install.

You have a really nice site and I am impressed. Also I think Tammy would say hello to you.