It seems to me that you're likely to protect it so much, no-one will buy it. Adding DRM will only affect your paying customers, not those who rip you off by downloading unauthorised copies.
Watermarking is the only form of DRM I'm happy with on my books, but it's not possible through the Amazon Kindle store, as it would require Amazon to provide it. Indeed, it's only possible at the moment through your own web site.
But unless you're J K Rowling, you're unlikely to draw enough traffic (& sales) to justify the set-up costs.