My kill that I'm comparing yours to:
https://www.warcraftlogs.com/reports...done&source=30
Your orb generation in general was quite low, as you generated 148 orbs vs my 200 orbs and I had a 30 second shorter kill time. Consider using a mythic GSR to increase your orb generation.
You also need to cascade at better times, ie when it will hit more adds. You cast it 13 times for 77 bounces and I cast it 12 times for 100 bounces.
I also cast MB two more times than you, and again, my fight was 30 seconds shorter. This means you were sitting on MB but clearly weren't being overwhelmed by orbs due to your lower generation. Get those MB out more often for more DP damage. Also, make sure you're dumping DP into a target that will live long enough for the full duration of DoT goes off, unless your guild was REALLY struggling with prio target damage and needed a gimped, non-full duration DP to kill Deathcallers or something. After saying all of this negative stuff, however, you wasted 0 orbs overall, so very nicely done there!