I think finally I figure out how to do that. Basically, when you trigger the cataclysm, the hurricane must be on. To say that. before you enter a new area, make sure you have 40 stacks of Force of Will. After that, enter the area, turn on hurricane, move around until your BacQax (or you can use FeoQax) fill up. At the same moment, get closer to as many mobs as you can (you need to keep using maul to prevent dying). Make sure your Qax is full and then turn on bulwark and cataclysm immediately. I did not pay special attention to quickshift stack, but by doing this, my damage can be up to 13T (the soul harvest with 42 mobs)!
What you want to do is pre fill both runewords before entering the pit. Use Bac to pre fill to the top without overflowing and switch back to IgniXan and FeoQax.
Combine this with what you are already doing and you will see even more damage. With max paragon and full tempers and GA gear, it is not unusual to see between 20T - 60T+
The important thing to remember is to keep mauling to stay fortified. This will keep your damage up due to fortified bonus to overpower.
Also side note, using emote will cause you to shift back. You can use this to quickly stack quickshift before the run.
jesus this makes me want to barf, the damage and snapshotting/gear swapping that is