When I was researching my DADGAD book ("The Irish DADGAD Guitar Book", first published in 1995 and still in print, I'm happy to say -- it's published by Novello & Co. under the aegis of Music Sales Inc.), I went to the library and got loads of music theory books out, in order to be able to give the correct names of the chords in the chord charts I put in the book. Then I happily forgot them.

In the book, I generally give two names for any given chord -- the "correct" name -- e.g. G6 (add 9) -- and then the functional name, which in this case would be G/A; i.e. while the chord is technically a G 6th with an added 9th, what I'm really doing is playing a G chord with an A drone. Similarly, Am (add 11) is really an A minor chord with a D drone. Hope that helps ....

Cheers,

Sarah McQuaid
http://www.sarahmcquaid.com