john pearse,analysed Browmnies guitarstyle in one of his books,he used a fingerstyle pattern,that pearse described thus;Agreat deal of fingerpicking uses pattern picking.this means that a particular rhythmic syncopation recurs throughout the tune.Brownie Mcghee is adept in this technique
one and- two[index thumb pluck together,middle then thumb]this is probably an over simplification.
sonny, played harmonica wrong way round.