I received the Gleim books also but went ahead and bought the software off Gleim's website for the instrument & commercial. Liked it more than reading the books, plus questions I had a hard time on or didn't understand you can mark and come back to later.
And as far as getting them done before starting the program, you do have time to take them during the program but getting them done before hand will give you a little more time, plus a little better understanding of what your doing. For example, having the instrument written done before starting the instrument training have me a good head start, especially with the quickness of the program.