It depends of the fight and your teammates really, when you want to apply TA, some prefer after 5th GCD, some SAM after the 6th (with the 3 sen opener). If you personally lose 200 total dps on parse but your team gains 100 each it's worth sacrificing your own, again if you are in a static or raiding situation.
Also, if you use raiton, try to use fuma except under kassatsu or if you need to reset shukushi, in order to not clip your GCDs to much.