I've been playing "help me" or "green onions" for YEARS & YEARS... "Sonny Boy" played it in "2nd position" on a regular 10 hole marine band or a 12 hole Echo Vamper... Depending on the gig... I can't remember the key he used to play it in. Probably an "a" harp playing in "e".... That is a guess! I could be wrong. John Walden London England