jimmy brown is best played using the Carter scratch.
maybelle carter generally used a c shape,played the melody on the bass strings with thumb,and flicked down with her index and sometimes middle finger on the off beats,she sometimes used a capo,and or often had her guitar tuned below concert but still in standard.google maybelle carter on you tube,youcan see her style from Wildwood flower.she also made extensive use of hammer ons.