People think Buffalo horn handles are hard, cold, and slippery but I love them. To me they feel soft, organic, and very comfortable, even with extended use. I keep mine conditioned with hooflex and soak in mineral oil. Both wood and horn handled kukri need to be treated with care, they take a tremendous impact with regular use and without care they will crack, break, or shrink and become loose.
If I were having a “user” kukri custom made I would probably try micarta or G10. If it were a show piece kept in a house I would find a nice piece of horn with some color in it. Beautiful and traditional.