switching over to arcane going into BRF and I'm curious what the rule is for using shards/copelands type trinkets with 2 minute cds is? macro them to arcane power and just go through burn phase regardless of when they're up? use them both on cooldown even though that would desync their cooldowns for 6 minutes?
Macro them to Arcane Power, but make sure you have a separate cooldown tracker for it, so you can use it when you're supposed to. As always, the general rule of thumb is to make sure you get as many uses as possible over a fight, then worry about how to optimise thoses uses afterwards - such as on mythic Butcher when you stagger your second use to line up with second pot + AP + racial (if applicable) + trinket.