Another thing you can do to improve the macro is to repeat the Trick Attack command as many times as possible. Macros do not queue like regular skills, so you usually have to mash them for them to go off, but the game puts a tiny delay between each line, so if you repeat an action a bunch it will keep trying to execute it for a quarter of a second or so, which acts almost like the skill queue.

Code:
/merror off
/ac "Trick Attack"
/ac "Trick Attack"
/ac "Trick Attack"
[repeat as many times as will fit]
/ac "Trick Attack"
/ac "Trick Attack" <wait.1>
/p Trick Attack used—10% dmg bonus on the boss! <se.1>
/micon "Trick Attack"