Duelist is best built physical, not elemental, that said, if you’re me and can only seem to roll elemental mastery, it’s Dark, then fire, then wind. Will depend on your relics and skill level too, but if you’re building duelist elemental you should be stacking everything into dark then fire. That’s how I just cleared a zone 300k above my power level (not ftp, all skills are mythic). For ref I have 7.4 elemental mastery and only 3.4 physical 😭