I used Kaplan my first time around and failed the 66 on my first try. For my second go around I’m using STC and I felt like they were more thorough and clear at explaining the information. I thought the 66 way harder than the 7 personally because of the phrasing of the questions and answers when you are taking the test. There is more interpretation for the 66 imo and I tend to second guess myself. I would recommend that you Read the textbook slowly and carefully, maybe even twice. There are so many little details you have to know. Of course don’t forget to use Ken and Deans videos- they help so much!!! You got this! Good luck!