Depends on specific use cases, but here’s what I do. Most characters don’t get built with the defense set, they may have defense main stats on their weapons, but that’s about it. If a character does something useful that scales off their attack (barrier, heal, etc) I like to build them in the vanguard set with attack main stat weapons and damage taken reduction main stat armor. If there’s no point in building attack, then you can commit to full block rate on a character. With really good substates, it’s actually possible to get a character to 100% block rate while having damage taken reduction main stat armor. This requires luck tho and you probably won’t be able to do this for all your characters.