Redecorating with Bookshelves

I completely rearranged the furniture in my guest bedroom/office, to make the office part more workable for me. At first I thought I'd get a couple more bookcases, but I don't have any money, I have a bunch of bookcases already and am getting annoyed at bringing in a 4th kind of bookcase that doesn't match any of the others. Plus, I remembered another option that I really want to try: Invisible floating bookshelves.

So, I found a video on how to make these. Unfortunately, I think the book you use as the base has to be somewhat thick which is a bummer as I had already decided on 4 to use and 3 are fairly thin (less than an inch.)

Has anyone tried doing these? Any tips/advice? Anyone had a bad experience with the invisible shelves? We're doing them with an L-bracket and wood screws, not with one of the kits, so the book on the bottom will be permanently stuck to the wall, so kind of destroyed/not accessible. But a heck of a lot cheaper than buying the fancy shelves, which I am not convinced don't hurt the books at all.