How much Accuracy do I need to hit Athena Pierce's Clone at a high rate?

Yes, as an Archer, you should cap your DEX at 200.

The only problem will be the possibility of her killing you. As long as you don't die, it'll be easy, and if you can snipe at her from the top of the hill while she's down the slope, you won't take damage until she summons.

Dying won't be a problem since I got 2.5k HP Base at Lvl 30, exspecting it to be about 7.5k at Lvl 70.

Edit; Btw, if the main post wasn't clear enough, I had problems beating the monster during the 2nd Job Advancement. I'm of course not Lvling my character the usual way. I'm actually PG leeching it.