Hi dmlocke,
I'm new to PR too and still getting a 'feel' for the techniques which are right for me. Just to let you know my story thus far, i have found that when i PR books on my personally favourite subjects i seem to be able to activate them much easier and they seem to 'gel' much quicker for me with information i require coming easy, this is obviously due to me already having some knowledge in this field and any further information can be easily integrated with associations and connections made.
However, when i try to tackle books with subject matter that is relatively new to me i too have difficulties with comprehension and ultimately frustration which leads me to end up wanting to read in the regular way, i do try to stick with it though and trust that it will come together for me as i make multiple passes and try to focus on purpose which adapts as comprehension slowly comes to me.
I know this isnt much in the way of advice as im new also but that i had the same experience with new or complicated material and that i think as long as you have a purpose and determination it will get easier as you learn to establish clearer and more focused purpose and develop awareness of communication between inner mind and conscious mind; i have found also, that it is really tough sometimes to define a specific purpose when all you really want to do is get a better general understanding of a subject.
Be nice to hear how you get on,
Be well,
Mitch.