You say 3 weeks so I presume you are off to the States. Well in my experience, you need to read all of the books thoroughly before you get there. There will certainly not be enough time to spare for any useful ammount of study. None of it is difficult, but if you are to learn to fly quickly and efficiently you need to know the theory.
I suggest you read all of the books (except perhaps no 5) and do the entire confuser before you go. Then you will be able to sit the exams when you get there to get them out the way, and use your knowledge to support your flying trainng.
Theoretical knowledge is not something you should skimp on when learning to fly.
Best of luck.