Your experience won’t help you much with exam 4. Exam 4 is the case studies and the PRMIA byelaws etc. 4 full days may very well be enough to pass the exam though. Just read through the material once very carefully, maybe also make short summaries of the cases. Then do some test exams to get used to the kinds of questions and practice good guessing. Kesdee has some exams for level 4 I think.
In my estimation reading through the material once suffices to remember enough to pass the exam.
good luck!