Don't incubate! After PhotoReading put the book down for a moment, take a bathroom break, get some refreshment make yourself comfortable and activate. So what if the book hasn't had 20-minutes incubating. The mind is still working on it as you start activating and all it means is activation might be a tad slower. You might need an extra pass as a result. So what?
At the retreat we PhotoRead and activated a book all within 30-minutes. From start to finish. No incubation at all. Some of us may have found activation easier if we had a little time for incubation yet we were all able to get a lot of detailed information in that 30-minute period. Did we want more? Perhaps. Did we need more? Probably not when you consider the 80/20 rule.
Alex