I H/H Hell's Precipice twice yesterday: once on my warrior and once on my ranger (after a failed PUG).
My warrior: uses sentinel armor and armor of the great dwarf for high elemental resistance. I would flag my H/H slightly behind and aggro the sparks of the titan, take most of the initial damage and then charge and release the H/H flag at the same time.
I used Tahlkora [WoH healer] Acolyte Jin [Interrupt Ranger] and Master of Whispers [SS] , Mhenlo, Lina, Cynn and Eve.
Used an IDS and +10 vs fire shield.
At the portals I used a long bow to pull patrols and then once portal has only wraiths I charged, not that it mattered much because I goofed at Rurik and aggroed the 2 groups of hands of the titan and still didnt have any trouble dealing with them.
With my Ranger I used Punishing Shot, Distracting Shot, Read the Wind, Dust Trap [great against melee], pain inverter, troll unguent, breath of the great dwarf
Used Tahlkora (WoH healer), GWEN (inspiration/domination : interrupt with empathy), and Master of Whispers as SS
Same Hench as Warrior. With careful pulling it was easy, and yeah Dust Trap was superb. Gwen managed to interrupt the mesmer boss's Cry of Frustration

. My PC crashed while fighting the Lich and I logged back seconds before my H/H killed him
Btw you can pull Rurik and the Sparks away from the Hands and once Rurik killed --> Cut scene ---> dont have to deal with the hands.