I have normal Bad Juju and Renataki's double upgraded (530) but I am currently using the Flex Assurance of Consequence, double upgraded (548) and the Timeless Isle trinket, Discipline of Xuen, not upgraded at all but considering upgrading.
I was thinking about switching to Renataki's and Xuen but I'm not really sure. If someone could help or point to like a trinket BiS list or something it would be greatly appreciated.
Does this statement assume that you're popping your primal fire ele at the very start of the fight?
Yes. If/when you have trinkets that don't line up so well, then you'd drop the FET glyph. Assuming 100% uptime on boss, this gives the FET a better shot of benefiting from the staggered procs when they go off.