For me, Mercy Stroke works best overall. Aside the occasional 5%-10% on wiffs (which happens, not much you can do about it), I think I do pretty damn good damage. Here is my gear set :
99 THF/WAR
Hecatomb Cap is augmented with +7 attack and +1 Double Attack.
Hecatomb Leggings is augmented with +2 STR and +5 attack.
Thokcha is augmented with STR +11 and Attack +22.
Food : Red Curry Buns
STR : 101 + 87 + 7 (food) = 195
DEX : 94 + 45 = 139
AGI : 91 + 1 (food) = 92
ATK : 664 + 154 (food) = 818
Double Attack : 12% + 10% (gear + sub warrior job trait) = 22%
1. SATA Assassin's Charge Stacked Mercy Stroke with Brew
2. Critical hit with triple dmg proc + triple attack triple dmg proc stacked
3. SA Mercy Stroke
4. SATA Assassin's Charge Stacked Mercy Stroke fully buffed with food and temp items (was over 1200 attack)
5. SATA Assassin's Charge Mercy Stroke fully stacked and buffed (no brew)
I hope to get 99 Mandau when SE fixes things with obtaining the items.