I took and passed the one week seminar and test in June and found it to be very informative. I wish I had taken the course sooner, as it was more in-depth than the online interpretation course I took through Worldspec years earlier. As part of the course, they gave us reading material that we had to return at the end of the week, and this is all I read in preparation for the exam. It would be very difficult to read everything they asked us to read after class, because there is not enough time to do so unless you are a fast reader. One thing that helped me out was that I took a film photography class through the local college the semester just prior to the seminar, and I was able to apply the fundamentals of photographic film processing to radiographic film processing, as they are very similar. I suppose, if your are a CWI and have a good understanding of the fundamentals of welding, I would recommend focusing on the books that are geared toward RT, such as the ASNT RT and radiographic interpretation books. I recall from class that the people who had previously failed the exam had failed the practical part. For this I would recommend getting familiar with the different terminology that is used in the different code books as API describes discontinuity types differently than AWS and ASME.