I have two Taylors that I keep in alternate tunings: one in open D (DADF#AD) and the other in standard D (DGCFAD). Both of the guitars have always used light gauge strings: d’Addario EJ16s. Problem is, in my alternate tunings, both guitars go out of tune constantly due to the slackened strings.
So I tried something new: d’Addario XTs in MEDIUM gauge. The added string tension keeps them rock solid in tune, and the XTs sound fantastic. Problem solved.