Itto is honestly pretty good at these sort of fights with multiple mobs. My rotation could be better as well as my artifacts, but I still was able to clear 8000 points without too much trouble. If I optimized it, can probably do this with 30 seconds+ left on clock. Build is at the end of the video if you want to see. I used serpent spine, but whiteblind (F2P option) should be perfectly fine too to clear this with 8000 points with ease.