Hi,
Sorry for my bad English.
I had the same experience before, although PR never work for me. But the ideas of "purpose", "only pick up important sentences", "mind-mapping", "trigger words" are good for me, I use them to speed up around 3~4 times with more overall understanding compare to normal reading.
I could understand your feeling, that is more like the brain is blank, overloading, could not read anymore, like a sponge with full water.
The reason , as my experience are :
1. Too much dense information , so I want to know everything while I am reading it.
2. I try to load everything to my brain in a short time(before that, I think I could finish it in 3 hours, but the result is more than 5 hours, so I have much pressure in my mind and brain) So finally I lose my way, I forget what should I read, I forget to refocus the purpose, I forget to ask a question. Did you ever lose your way? At that time I feel I don't know what should I read, I just read, so finally I am back to the normal reading with insufficient time. And in the end my brain is blank, overloaded.
So my solution is that : every time when I lose my way, I just flip the page back to the catalog, to check out where the lighthouse is. Or you could simply look back to the trigger word list.
And one more thing is that: You should have a main structure in your mind while reading. So that you can always know where you are, like the real map, then you'll never lose your way. The reason that you could not formulate the basic thoughts is because you could not link the chapter/book to the ideas(memories), because you have no map in your mind. The suggestion in the PR program is to draw a mind-mapping. But to me, personally that suggestion doesn't work. I still lose my way because I'd put all my memory to that sheet, but not my brain.
If you want to find something easily in your room, then before that, you should sort out every thing in your room. If the room is mess, than you could not find(link) the thing you want in a short time.
As you said "I feel I am starting to put the huge mountain of information together." If your room is mess, then you will feel much stuffs in your room. But if you sort out them, you will find the huge different. I think you could gain the real experience from the real world
->order your real room first.
The "room theory" could be find everywhere in memory-training books. I just link the "real mind-mapping" to that idea.
Not very detail, but at least you should have a main branches in your mind. And you could put the detail in the mind-mapping.
My personal experiences and thoughts.
LT