Hey Mike,
You came to the right place for information. Many people respond differently to different types of prepararation. I have not tried the weld acadamy course or the AWS courses. Your type of question is frequently asked here.
In my opinion you can't go overboard learning provided you keep it in balance with the other things in life.
As far as preparing for the test it will depend greatly on what areas you are comfortable in. Some people test without the courses and some with. AWS doesn't provide a pass/fail percentage based on preparation method.
I suggest as much self study as you can stand. Study to learn the material for what you do at work or what you want to do. That way, pass or fail you have increased your job skills. If you aren't interested in the subject matter and find it hard to just sit and read through technical type material, a course may be most helpful. The seminar will help you prepare for the exam. It may not prepare you to be a welding inspector.
Do a search on this forum using CWI EXAM and various other keyword combinations and you will see great deal of information on this subject.
I suggest being familar with ALL of the content in the AWS Welding Handook Volume 1. Not verbatim but its a very good reference to browse through during those "casual readiing times". Terms and Definitions, Welding Processes, NDE Processes, Metallurgy, etc.. "IT'S IN THERE"
There is my opinion for now. Many fine and credible opinions will follow. Look at them all and apply the parts that most fit your situation.
Try out the welding quiz at http://www.weldinginspectionsvcs.com/QuizRev1.htm if you haven't done so already.
I hope this helps and feel free to ask all participants as many questions as you need.
Have a nice day
Gerald Austin
Iuka, Mississippi