Here's my method (basically with post-GC a lot of Choice's tricks that were originally required to beat the fight aren't anymore, so I took the dumb way out):
Phase 1: Don't infest game. Just walk in a circle, let as many Horrors and Ghouls up as possible. Don't consecrate, use HA/AW on CD for DPS. Phase should last about 3:30-ish.
Transition 1: Stay until LK is down to about 68% (1-2 ice spheres) then run to the throne, kill raging spirits (you should be able to kill all 3) before LK quakes and becomes active.
Phase 2: Burn LK, begin using Consecrate at around 50%.
Transition 2: Stay and burn LK down to ~36-37% (1-3 ice spheres), then run to the throne again. Consecrate in your rotation. You should be able to kill 2 raging spirits during this transition, then begin focus on LK. This means you only have 2 spirits up which gives a lot better survival chances in P3. Should be done at about ~9 minutes.
Phase 3: Burn as hard as possible, make sure you are getting your spells (consecrate, how, hw, and especially execution sentence) out when not silenced. When pulled in try to get a sacred shield at the last possible second of your vengeance stack, make sure you get 5 HP from judging before you get out.
Try to survive Fury of Frostmourne so the fight doesn't bug out.
Gear: ~519 item level (ret gear + 1h + shield) with LFR Ji-Kun's trinket.