Getting 20 out of 20 is a perfect score, what you need is the 5 patterns of the major scale / pentatonic scale / CAGED system. Knowing this will make your practice of the scales a breeze. To me rhythm or strumming is important while lead guitar like blues or rock is secondary. The message of the song and melodies is what makes it to the top charts. I am just a mere beginner but I know the 5 patterns because of previous books and pdfs from various authors. This 5 patterns are here in Guitar Tricks ( i'm sure of it), suggest you start with the Guitar Fundamentals 1 and 2 , save the text lessons on pdf format for review. I am just starting on Country Style 1 and my timing is off.