Yeah, you pretty much need to know everything, and please do not neglect governmental and not-for-profit organizations.
I am not sure if my study approach works for anybody, but I went through all the video lectures once while taking pretty thorough notes (using Rogers). I did not do any questions besides the ones in the book that Roger goes over. Then a week before the exam, I revisited the notes, and did about 10 questions per chapter (Rogers is broken into 30 or 31 chapters).
My mindset was if I knew the materials, I should be able to do the questions. So, literally, I did not practice any MCQs until the final review.
I overall studied 1 month for the exam. 3 weeks to go through the materials and one week for final review and practicing MCQs. I never looked at any simulation practice questions in the review materials (same thought, if I knew it, I should be able to solve it)
I was working full time, so after work, rather than going home, I stayed in the office, study for 3 – 4 hours (Mon – Thurs) and 6 – 7 hours (Fri – Sun). Because I was short on time, I did not take a day off.
I ended up with 81, so I guess it worked. Without going through hundreds of thousands of questions, you can still pass if you understand and know the materials.
Good luck!