I would like to thank everyone for all critics that my video got!
I've made some clarifications:
1)for "8 second" Locust Swarm: Even though we run with Creeping Death and Locust Swarm DOT's supposed to last forever(in fact around 6 minutes) instead of 8 seconds, you still need to recast locust swarm on new mobs when you move a screen away to a new pack/etc, so hence where the mana cost are problematical if you run with Furnace. And it's actually very hard to even see what mobs have locust swarm of them in all this mess on screen. Also when you consume all Locust Swarm DOTs with SH, you ALSO need to recast it once again.... And single Locust Swarm cast is 300 mana. 3 Casts and you are out of mana.
2) For Soul Harvest = even though in video i say "use Languish", it does not really matter since 4pc gives us all runes. An old habit from running other sets and builds :))