HSG, I would certainly agree that you need to understand the subject, not just work off feedback questions. If you work from feedback alone you can come unstuck when the exam questions fail to match the exact wording of the feedback questions, it only takes one word to change the sense of a question and sometimes the correct answer as well. By the same token, it would be extremely difficult to pass the exams without feedback because so many questions are completely 'off the wall' and, in some cases, arguably outside the published syllabus.
Cabair's CGI is excellent, and the fact that you speak so well of him and his staff is all the recommendation they need.