Optimal isn't really out there yet. With parsers unable to accurately determine how worth it DoT are and mechanics being different there isn't really an Optimal rotation. An effective rotation would be the simple Dragon Kick -> Twin Snake -> Snap Punch from the Flank. That way you can focus your efforts on dodging red. I recommend learning your lag. You can run out of a circle and sometimes theres a delay and you'll still get hit by an AoE even though you were out, the same is true for reverse. So if your lag is like .3 seconds behind, run back into the circle at the last second. It can save you your GL3 stacks. Fights like Titan are just plain hard to maintain GL3. Garuda and Ifrit aren't too bad for the exception of their vanishing acts.
I like to save my perfect balance for after a vanishing act in hard modes and use to to reclaim my GL3 very quickly and reapply DoT. The beginning of the fight isn't as important as the second half for primals.