"Holding this C chord position down with the left (or fretting hand) hit just the single C note (5th string, 3rd fret) with the thumb (down-stroke) and then sweep the other strings (strings 4, 3, and 2) again with a down stroke. (All of the strokes here-on-in are downstrokes all played with the thumb.) Then, sweep the 6th, 5th and 4th strings together with the thumb, followed by another sweep of the thumb hitting strings 4, 3, 2 - and 1.) Repeat this entire pattern until it feels comfortable and sounds like music." --JP

So at this point you aren't actually playing an alternating bass with the thumb? or is the second "sweep" suppose to be the second beat of the alternating thumb bass (Just that, as you are describing it and we are to yet find out....the second thumb beat isn't a single note?)