Do I macro them in with Flame Shock so that they're nearly always on cooldown, or do I macro them together with Elemental Mastery so that they're active during my %Damage buff? (I'm assuming I should be casting my %Damage buff during Heroism, when possible, right?)
For reference, my character is at http://us.battle.net/wow/en/character/hyjal/kaezoku/advanced. One of my trinkets has a 2 minute cooldown, the other has a 1.5 minute cooldown, and Elemental Mastery has (I believe) a 3 minute cooldown, but is lowered by my compulsive lightning bolt casting.
I find that my short-cooldown trinket (which has a flat +Spellpower effect) is rarely on cooldown, which means that I don't use it often enough. I can't seem to use it AND the longer CD one (since they both add spellpower, I assume) at the same time, so I'm looking at a way to make sure it's not just wasted stats (despite looking good on paper). While I feel like it's suboptimal not to guarantee that I'm stacking them with Elemental Mastery, macro'ing the trinkets to my Flame Shock would come pretty close to approximating the on-equip trinkets' uptime and therefore I think it ought to give me better returns.
