You can find detailed information about that in the sticky at the top of the barb forum by Raging Koala. But The 1.67 BP is achieved with a 1.0 skorn and 42% IAS, 1.82 with a 1.0 skorn and 57%. This is if you got a non IAS skorn which if budget allows most run with a LS skorn. It allows us to not use bloodthirst and an IK belt. But you really want to have high CC as well with 28 being the lowest, 30 being comfortable, and 35 being ideal.