If you keep Rook Overdrive aligned properly with other raid buffs in a meta comp, you will use it at about every 2 minutes. That means at about 0:20, 2:20, 4:20, 6:20, etc. of every zero downtime fight. Meta comp includes DRG, NIN, SCH. Having a BRD and AST helps out your DPS too. If you have a Ninja, Rook Overload will hit right after the last charged auto-attack from the Turret and before Trick Attack's 10 seconds wears off .

Every 0:20 and 6:20, will be your biggest burst with Rook Overdrive. You have Battle Litany and possibly Dragon Sight buffs (but most DRG will give to BRD or melee DPS/WAR), Chain Strategem, and Trick Attack. If you have BRD, you get Battle Voice and possible Foe's Requiem.
Every 2:20 and 4:20, will be moderate burst with Rook Overdrive. Same as above except no Battle Litany nor Battle Voice.

General idea is to always use your strongest cooldowns and moves during buff windows.