I'm going to use the crafted 496 chest as an example. It has two blue gem slots and according to the guide posted it's best to use the int/spirit gem. But why wouldn't we use the mastery/spirit gem. We're still getting the +120int socket bonus. Yes, we lose out on 160int but gain 320 mastery. The gain to spirit remains the same.
I guess basically what I want to know is at what point does "x" amount of Mastery out weigh "x" amount of int, or is there not a point at which this would happen? Is 320 mastery > 160int?
I would link the chest and gems but have no idea how to do so.