If you have access to beta i suggest starting to practice these types of pulls, ledge will most likely be fully fixed by release and yet normal slave pens is still the best xp per hour at 400k/h.
Ill do a proper guide when i do some more tests, these are the extremely useful weak aura paste bins:
-WeakAura for Cripple: https://pastebin.com/Vf4F4VgP
-WeakAura for Immolate:https://pastebin.com/n6ruPhn5
-WeakAura for Lightning Bolts:https://pastebin.com/1r0VkmqJ
00:00 First pull
07:54 Second pull
11:47 Third pull
16:47 Fourth pull