Hey,
At first, 1/3 the time it would normally take you to read the book would be the presumable time to get detailed comprehension using photoreading.
It gets faster the more you use it.
The key is to keep activating the book in layers. Super read the book 30 minutes or so after photoreading.
Then super read and dip the book. Then if you want more comprehension, super read and dip the book again.

Each of those segments should take about 30 minutes, except for the photoreading step of course, which will only take between 5 and 15 minutes depending on the size of the book and the time it takes to get into state.

-JackTuff13