A good basis to determining BiS is clicking on the Weight option on Ariyala's site.. This isn't always a perfect rendition as you may need to swap around gear based on your stat needs, but helpful nonetheless. Once you reach those stat caps, it's all a matter of knowing the mechanics enough to maintain your DPS. Higher gear or better melds only offers you more breathing room. For instance, you'll see some people meld Vitality on their accessories if they don't yet have 230 on their right side. You don't technically need it until A8S, however you will have play near to perfection because your HP pool won't allow for mistakes. Best thing to do is hit the necessary stat caps and practice your rotation. Brannigan summed it all up well. While stats do certainly make a difference, you knowing your job well will come ahead, especially in mechanic heavy content like Midas Savage.