what little I know came from John Harrison, ex Waterson. He instructed me that playing banjo the re was no third note in the chord eg. when playing in G the B in the chord is lifted to C. how he did it on Guitar was to mute the B string and in D he would mute the Fsharp. hope this helps. I find it easy on Banjo as I just lift the B and play out in modal. Hope this helps