I arranged Silent Night for solo hammer dulcimer, for Dulcimer Players News, so many years ago. My first band, Gladly Play Wyth Stryngs, used the simple single-HD arrangement as the last selection on our 2001 Christmas CD, Glad Tydings.
Attached below are a PDF of the arrangement, and a sound file of it, from the CD. My best to you all.
16 Silent Night.m4a