Dropping Grit

[MauvaisOeil]

Never Dark Arts Power Slash. It's a pitiful one point modifier increase, and that's without factoring in the weaker damage. You are far better off turning Grit back on temporarily and doing either a DA + Souleater combo or a full Power Slash comboing, then dropping out again. This gives you a significantly higher lead so you won't have to Power Slash again for a while.

A good rule of thumb with PUGs, OP. If you have competent DPS, particularly a Samurai, Black Mage or Red Mage, start with Unmend and two Power Slash combos before dropping Grit. That should give you a solid lead through their respective "burst" phases. This assumes your co-tank isn't using Shrik or you don't have a Ninja.

Since Stormblood, DA PS is twice the threat of PS itself.