I've been working on some solo guitar arrangements lately. For the holidays, I've been fooling around with playing the beloved Christmas carol "Silent Night" in DGDF#AD tuning. This song has been arranged for just about any combination of instruments and voices imaginable. However, I wanted to do something with it that would give me a little ownership , so I chose a tuning that I've used on a few of my own original guitar pieces — like my "South Branch" piece.
It turns out that this DGDF#AD tuning works nicely, and it allows you to easily leave open strings ringing in the same way a piano player might use a sustain pedal. I'll use anything in my music if I think it sounds good. Letting open strings sustain works beautifully on this one, and the use of unison strings sometimes created a harp-like effect.
Be sure to bring the melody out by playing it with a bit more volume and emphasis than the (usually lower) accompaniment notes. I tried to vary the location of the melody across different strings to take advantage of tonal colors, but you should consider exploring other places on the neck where the melody works. When I begin an arrangement like this, I like to try out different ways of playing the melody before I even worry about harmony and approaches to accompaniment.
This arrangement is simply meant as a guide. I don't play it note-for-note, and I'm still working on a longer arrangement that moves to a higher octave with a little more variation. Enjoy.