So actually, if you are teaching the Dennis Kamakahi tune, you will be teaching slack-key guitar--

According to his liner notes, Dennis plays "He'eia" on 6 string in "C Mauna Loa Tuning (C-G-E-G-A-E)", only tuned down a full step to Bb (Bb-F-D-F-G-D)--seems like it would loose a lot of the flavor in D tuning--