You can use PhotoReading on all material.
A few years back I grabbed a couple of dozen books on Shakespeare from the library. I PhotoRead a book a day for a few weeks. Then I curled up in front of the fireplace with a Shakespeare play, and for the first time in my life I enjoyed Shakespeare. I could understand the play. I realized why his work is magnificent.
I've talked with English teachers who said that their understanding of a play improved dramatically when they PhotoRead other plays by the author or of the period as well as any critical reviews.