Listening to live RT is probably the worst thing you can do prior to a RT Test. Firstly, you should have practiced the necessary RT as part of your training either in the air or in the class room. The purpose of the test is to see if you know how to do it correctly, not to see if you can copy all the bad habits you heard on the air. A typical RT course will last about 16 hours, then you should be proficient and find the test quite straightforward.