I have a Discus-2 and don't like its headrest one little bit. To my way of thinking, I don't want a headrest at all. I want a neck rest. For the last 20+ years I have used a 4 to 6" neck roll. Diameter dependent on what it takes to put my head in the right position to see over the nose. My neck roll is about 2 feet long and sits on top of the parachute. A neck roll allows me to swivel my head from side to side with no interference with my hat (headrest moves hat when head is swiveled). My neck roll is made up of my land-out jacket and rain slicker that is carefully folded and rolled up with large rubber-bands on each end to keep it together.
Works for me,
JJ