Paul,
My comments follow, but I feel obliged to point out that I feel that these types of matters are extremely individualistic. What works for one person may not work at all for another for any variety of reasons, not the least of which is how we react when struggling under the pressure of answering 200 questions in only 4 hours! With that caveat, here are my thoughts:
I would recommend, based on my experience, that you go ahead and brain-dump the process group/knowledge area mapping along with the 47 processes. I did this as part of MY brain dump along with just a handful of formulas that sometimes tripped me up when I was feeling time pressure during the practice exams. This took less than 10 minutes. And while around the mid-point of the exam I was slightly behind schedule, I ultimately ended up finishing the test almost 20 minutes early. While I could not have known this going in, the brain-dump time did not hurt me in passing the exam. Here is why I would tell you to do it:
1. Psychologically, it felt good to have the list to lean on. While you might not have needed it when you were taking the practice exams, that may be only because some gap in your knowledge wasn't exposed based on the questions you randomly saw during the practice exams.
2. On some of the trickier questions, I found it helpful to look at good ol' Table 3.1 to think something through.
3. A few times I looked at it just to confirm what I felt I already knew (this was reassuring for me, because one of the obstacles I had to overcome was that about 50% of the questions I got wrong on the practice exams was due to the fact I would read a question too fast - looking at the brain dump chart to think through the process in relation to the rest of the processes helped me to slow down and double-check). As Cornelius says time and again, you really need to read the question carefully.
4. I'm not a neurologist, but I'm guessing that the brain dump before taking the test will help to refresh and activate your process knowledge and may be contributing to your good practice exam scores! If you are doing the brain dump and being successful in the practice exams, I would hesitate to do it differently on the day of the actual exam.
Of course, your mileage may vary.
Best of luck on the exam!