Theoretically true strike can produce, but realistically, twin wins out. You are applying everything 100% uptime from auto attack to off gcd attacks to shoulder tackle, etc.

In a real boss fight, you will loose your buffs, the more you over lap them, the less chance of losing it.

Let's put it this way, do you want some who:
does 100% out put on inital-phase 70% output on mid-phase 30% output on end-phase
or
does 70% out put on inital-phase 70% output on mid-phase 60% output on end-phase

100% of the time I would pick the latter. Parsers can go up the rear for all I care, because parties aren't worry about who does the most damage, it's who wins the fight, and all that matters is the last stretch of the battle.