Do it, Taurus gives her a permanent increase at the expense of longer delay between each turn...but by the end it's like 175% with chance of crit and deathblow.I didn't put Taurus in her yet. Oh the possibilities. I got Fie at 100% and she almost never gets hit. It's kind of nice.
For Fie be sure to also give her the quartz that makes her crit everytimes it's a counter attack too! Juggler is good because maxed out it's 50% chance to inflict random status with an Attack/Craft and 50% chance of Nightmare too. Considering her crafts are pretty much AoE you get the idea!