Jack,have you never heard guitarists bending notes, those thirds can be bent,just like the third note can be bent on a harmonica,
it all depends on the guitarist,my whole point about modal dyads,the major and minor thirds can be left out,then your recorder player,has complete freedom.
Jack thats one of the advantages of DADGAD,and other open tunings,it is easaier to do it,but it can be done in standard tuning.
now here is one way round those dissonances of equal temperament,on an english or anglo concertina,instead of holding a major third for a crotchet[whole beat ]you play one note for half a beat,then touch the lower third for half a beat.here is an example of that.
http://www.youtube.com/watch?v=4K4-2laAOkI&feature=channel_page