Hello, Zak. I am not quite sure what you mean by
all the material and
3 CAT exams. Have you gone through the Official Guide and Verbal and Quantitative Review books? Did you complete three
official CATs? (If so, you must have access to a fourth.)
I think one more CAT would be fine to take within a week, but the majority of your preparation should be centered on review. You can identify your weaknesses by tracking the questions you have missed and, if possible, identifying what had caused you to miss them. (Have you been keeping an
Error Log?) In Verbal, it is more important to understand the reasoning behind
incorrect answers than to know how to justify a single answer in a given question. This holds true of RC, CR, and SC. Meanwhile, in Quant, you could be missing questions because you have conceptual gaps, or you could be falling into traps. Again, the review process can help you identify the types of mistakes you tend to make.
Two weeks can provide enough time to shore up your weak spots. Just do not go too heavy on solving new questions, especially third-party questions, a process that can fuel anxiety and not lead to any real gains. Sure, taking on a few new questions from an official source may not be a bad idea to maintain your test-sharpness—you might want to try questions from the GMAT Advanced pool, for instance, or even from those tagged "GMAT Prep" if you do not intend to pay for additional official CATs. However, overkill is a common mistake, and you want to feel as relaxed and confident when you go to take the test, not burned out and discouraged.
I hope that gives you some ideas. Good luck with your studies.
- Andrew