Pull your Faust in Deliverance, tell your group to kill the other one first so you don't have to worry about enmity. Depending on the rest of your group's DPS, you could be able to use Decimate during Berserk instead of Fell Cleave to do some extra damage to the other Faust. Use Berserk and IR on Faust, they'll be usable again on Hummelfaust when it's almost time for the other tank to Provoke off you. When you're tanking Hummel, you shouldn't need Defiance if you have Vengeance, Thrill and Convalescence available. If your healers are up for it, you can Holmgang the stacking debuff and let them do some extra DPS. Use Fracture if you'll get the full duration out of it.