Its been a long time since I've taken that test. At the time, the test was drawn from the same bank of questions. You just had to answer a whole lot more of them. I'm guessing that is still true. Just go with the instrument written. You will need that specific test to take the practical and why risk a failure. There is a lot of material to learn, and you will. Its great to get a head start, but don't forget you need to learn to handle the aircraft without outside reference. You will learn the relationship between pitch, power, airspeed and performance. Knowing what settings are needed for various configurations and the relationship between them are very important. Follow through and complete the task when you change configurations. Proper use of trim is also very important. You can practice this under visual conditions by yourself. Having said all that, I found the instrument rating to be one of the easier and more rewarding ones.