McGrath, I totally agree with the different cognitive styles thing and with the desireability of learning to play more accesible music and get accustomed to playing in time and making transitional runs before getting into advanced technique and theory. Still, sixth and seventh chords are about as basic as they come. In bluegrass music dominant sevenths are rarely played by the guitarist but a sixth chord will actually pop up once in a while. Major sevenths are admitedly rare in bluegrass. The reason I chose the exercise I did was because, for all the finger movement, only the D string actually moves. The others remain unchanged throughout the exercise. I guess I secretly hoped that some inexperienced but obsessive new guitarist would see it someday and get excited about it.
Murray, I have to say, I'm really impressed. Your method of learning to tune by intervals is probably some of the best ear training you can do. When I was a child, my father would try to teach me to tune his violin by singing "my dog has fleas" and tuning the strings to the sung notes. I never told him that he could't hear (or sing) the difference between D and C#. *BG* He loved playing his violin but he really shouldn't have been allowed to touch one.