How the would you do 600/800 questions per day ??
My method is to read the theory once, then do half the questions of the QB (paragaph by paragraph, for instance I read about hydraulics in AGK, then do half of the hydraulics questions in the QB)
This gives me a score of about 75-85% on the first takes.
Then, once I've done that for the entire subject I will do the other questions. My scores will improve over the second half of the questions because they tend to repeat themselves, and I reach about 90% on the last unseen questions.
Then I will revise, about 200Q per day, and my scores will vary between 85-100% depending on subject, luck, etc.. For instance there are a few questions in AGK that I need to revise very regularly to remember.
I'd say that in total I will have seen all 14 000 questions in the bank (except for flight planning, I really have better things to do than FP questions), and maybe revised a third of them, so 20 000 clicks total.