I was in two study groups (10 people all passed) for this test you can see a complete list of what I used to study here.
I took the NBCOT official online practice test from the castle website. It was very much like the therapyEd practice tests, in fact I failed it just the same :) (actually I did much better on the online test than the therapyEd test, but still failed it). I felt a need to do everything I could to pass this test and taking the online test was just one more thing I felt I had to do.
You have already spent so much time and money to get your masters degree in OT. Wouldn't it make sense to spend a relatively tiny amount on something like a practice test, as you probably have with the therapyEd book, and a study guide. If you do not get your hands on these materials and fail - then you will kick yourself for a long time, because you can't retake the test for a long time. Play it safe, you are already committed to this as your profession by this point and finish it off get what you need to put yourself at peace with the effort your going to give on the test.
The nbcot facebook page has some good discussions about the cost/benefit of some of the study materials.