This build is working out great for me: https://eu.battle.net/d3/en/profile/MarcusFunk-1813/hero/99149935
It's originally from this guy on youtube: https://www.youtube.com/watch?v=pkyZ-ZT-oQ4
The build is focused on keeping up Land of the Dead - Frozen Lands as much as possible while reducing the damage the mobs deal to the group and increasing the damage the mobs take from the group.
I have been clearing GR90's with easy when the others in the group is doing their job correctly. Toughness seems good in the build. Notice I am not using the exact same items since I had Primal shoulders with better stats etc. Just focus on getting the CDR on all items.