perhaps rather than being "frustrated", try "excited"... if you think you are frustrated you are setting yourself for failure.
The way I thought of photoreading before I got my "whoa" moment, was that the process of extracting important information from the book, without the photoreading aspect, would significantly reduce the time to get the information required anyway. Having a purpose, previewing, super-reading and dipping are all very productive reading tools on their own.
So whatever I got from the photoreading aspect was a bonus...