Chess e-book questions.

Hi all.

I think I have over 400 e-books and different articles about chess, really, of all kinds, on my computer, so I thought I should buy an e-reader (which I just have a day ago), but I have a huge problem with it.

All of these e-books and articles (well, about 95%) are in PDF format, which I thought the simplest of readers could handle (I've a Pocketbook Basic 2 model if that tells you anything).
Well, it turns out it can't. All of the diagrams are out of place, the lines are melting together, and overall, none of the books are readable.
I have downloaded Calibre, as everyone said it's the best converter program for e-books, but sadly, nowhere on the internet I could find which format is the best for chess e-books.

Please help, as reading these chess books was basically the main point of buying an e-reader, and I'd rather not throw my money out the window.
Anyone out here reading chess e-books? Which format is the best for diagrams?

This thread seems relevant. http://www.chess.com/forum/view/chess-equipment/what-is-the-best-ereader-for-pdf-chess-books

Various people opine that reading a chess PDF on an ereader is impossible and recommend getting a tablet computer or using your basic laptop or PC.

Well, thank you, though I know about this.
The reason I want to convert them is that I don't have to sit for hours in front of a shiny laptop killing my eyes to read them, but have it in my hand anytime I want.
I have tried several formats already, but none of them seem to work correctly (missing diagrams, lines disappearing, etc.).
It just seems weird that there are no suitable format for books with diagrams.
Well, thanks, hopefully someone comes by that could convinve me not all is lost. Of course, it still worth the money, as I have tons of books, it's just bugging me that the main reason I bought it for simply shows me the middle finger.