Ok, I don't want to be a dick, but some things need to be said.
1) page 5, the text between the characters is to small, in cases like this, could you put the page through a waifu2x pass? it will scale the image up and for the most part increase image quality though more or less magic, the increased resolution makes small text easy to read, and any browser or program based scaler will be able to fit to window size, so don't worry bout going to big or small.
2) page 11, 12, and 15 are kind of a cluserfack to read, i'm not asking for perfection, in fact, you could get away with doing 0 editing in these areas if you added a 5-10 pixel white background or a 15-20 white background that's feathered, while it would be preferable to go in and edit the page to just get rid of clashes and add the easy to read background color manually, I get that you may not want to do that.
If you need someone to come in and do these edits for you, i'm sure you will get offers as the work is very easy and as far as I can tell and the book is fairly popular, my estimate is that outside a waifu2x pass, saving the images will take more time then editing them for anyone who has done this before.