@pharphis better the merc than you.
Not understanding how the quests worked properly back then I partied all 8 players to kill Duriel in normal to get the quest with a L25 Sorc and used an entire belt of rejuvies and healing potions with Blizzard, GS, static and a lvl 2 BO, a 1 Pdiamond large shield and a Merc which helped a lot. The Merc bit it in 2 seconds. Just had only 10 FCR so the spells were interrupted regularly. I was 1 hit away from croaking it when Duriel bit the dust as the BO had run out. So it is doable with the Sorc. With the Barb probably LA is a good option with no to hit check, or concentrate to prevent interruption if you have leech, some +mana items and 30 sec BO and rejuvies.
Not understanding how the quests worked properly back then I partied all 8 players to kill Duriel in normal to get the quest with a L25 Sorc and used an entire belt of rejuvies and healing potions with Blizzard, GS, static and a lvl 2 BO, a 1 Pdiamond large shield and a Merc which helped a lot. The Merc bit it in 2 seconds. Just had only 10 FCR so the spells were interrupted regularly. I was 1 hit away from croaking it when Duriel bit the dust as the BO had run out. So it is doable with the Sorc. With the Barb probably LA is a good option with no to hit check, or concentrate to prevent interruption if you have leech, some +mana items and 30 sec BO and rejuvies.