Great suggestions! I have a reasonable library, and I really worry about not getting into the books I already have, but I sort of came to the same conclusion as you — read as you see fit! I think, for me, I like having books as a resource because I know of the items I have I can look and review something whenever a random intellectual thought creeps into my mind.
I do have a reading tip for you, Tobias, and anyone else trying to get through dense academic or even technical books. Usually, they are framed around some sort of organizational structure sort of like an esssay. Read the book’s Introduction/Preface and definitely hash out the thesis. When you start reading the chapters, read the first and final paragraphs but only skim the opening and closing sentences of each subsequent paragraph between. You just need to gather the gist of the argument/points. It really can save time on reading because the meat of paragraphs in this form of writing is to provide support for their points. You can always come back to that — the beauty of reading the way you want.
If the author did his/her job, then you would have the essence of their argument and you can hone in on the important study afterward. It certainly helped me in school when I had to read lots of books for research papers.