Textbooks take more activation passes so stick with it. Also use skittering for many textbooks that's a better option than PhotoReading.
If you don't have any questions you'll not find places to dip during superreading so it's important to have your mind probing questions in mind. You're not trying to comprehend everything that is written in the traditional sense you are aiming to find the important nuggets of information that concisely build the understanding you need.
Authors tend to repeat themselves and what you are looking for is the passage that sums it up for your conscious mind because your non-conscious mind has already processed it.
Alex
