Spider John Koerner pioneered the seven string with the octave G added to the regular G and put it to good use on the Blues, Rags and Hollers and Lots More B.,R. & H. albums.

George Van Epps pioneered the arch top seven string with the low bass string. He made at least one lovely album with no back-up players, though you'd swear he had a bass playing with him.

I think Lenny Breau is the best known player of the nylon string 7 string with the extra high string. I think Lenny used fine fish line for his high string.