My pleasure. Shoot me an email at jordan at birnholtz dot com if you'd like any notes or supplementary texts (or just a friendly chat about the subject).
The Little MongoDB Book might help. It doesn't answer all your questions but it gave me enough background (albeit MongoDB specific) to learn more. It's also a fairy short read. http://openmymind.net/mongodb.pdf
The Little Redis Book [1] might be better. Redis is easier to pick up and probably more useful as it's more complementary to existing database options.
https://www.youtube.com/watch?v=OX9HJsJUDxA&list=PLai5B987bZ....