Fire druid or wind?

Offline single player. Have taken my druid to level 81 p8 hell act 3 now. Have re-spec into wind. Have all the key caster gear. Have plenty of runes to make most rune words. Plan with character is to grind to 99, run TZ and MF ( aim 200-250 MF). Which elemental do people recommend and what merc set up?