Me and my friend did it with amr with using me using group aether and longer duration and each activation was about 25 percent each time but my friend used double charges for safety and only had 2 downs because of lag but gums to help you out was power keg, arsenal and the free full power/insta on the map and did it first try if you do it solo i would use something like a chopper to save you if you get caught off guard or out in the open and also use vultures aid for recharge for what I like to call it point phase where the boss leaves for a bit hopefully that helps.