By the way, this is what I plan on wearing while going through hell.
Helm: Peasant Crown
Wep: Hexfire, would rather have Wiz Spike...
Belt: Glooms Trap
Boots: War Travelers
Gloves: Magefists
Rings: 2 Nice resistance rings with 10% faster cast
Ammy: A nice +1 Sorc skills prismatic Ammy
Shield: The Ward (Perf Dmnd) 61 All Resists
I have a lot of life and resistance charms also.
On the questions of skills. I tear NM Mephisto up. I use the moat trick only to be safe, I could easily go toe-to-toe with him. I dont use fire ball to kill him though, because using the moat trick, most of the fire balls miss him. Meteor is a lot more effective, for me at least.