This website is great. The page I posted is a great starting point but I'd read the entire website, in further lessons you will REALLY notice how much some of the licks in these exercises sound like Dan. As it says, you don't have to use your middle finger as there are no hard fast rules, just replace the M's with I's.
http://www.fingerstyleblues.com/lesson-7-starting-with-the-thumb-independence-exercises/