hello
1- you will never master this exam. dont expect that it is like exams we did back in our pharmacy schools were we had specific materials to study and the questions will come from them, it is not like study hard you pass. how long it takes depends on several factors: fresh graduates, former experience in working in hospitals and your clinical background. it is not how long you study, it is what you study. in general I assume that 4 month with 6 hours every day is not enough to study every thing but it may be enough to pass. Also it depends on you, when you study any chapter what you focus on, what you think is important and could be a questions on the exam. For example, take a look at the pharmacokinetics chapter in Apha, there are a lot of complicated equations that I will never waste a second studying because I am sure I will not remember them. I know that a lot of test takers said they are important and we have to focus on them which is really silly. Also, that chapter is not fully understood from both Apha and Cpr but if you search online you may find simpler materials or resources.
2- I agree with you about the blueprint. people study Apha, Cpr without comparing their content with the blueprint. I mean you may study something that is not required when you focus on the whole cpr book. the best strategy is to read about any subject from different resources and simply GOOGLE It.
3- the first 12 chapters, 17 and 18
4- I dont know about this websites, but here is the thing, are they the people who make this test? then yes. do they refund your money in case you dont pass? I think it could be a good choice in case some one did not pass after 2 trials.