INT increases the FA's damage. I don't know what equips are good for FA snipers in high rates and I don't know if you have custom items there, but I do recommend these for low rates... These might be the same for your server and for HR. I haven't checked in with the latest equips in RO for a while now, so I don't know if there's anything better. But this is good enough.
Sniping Suit  x2 [ Peco Peco Card & Pest Card ]
Bazerald [ There are better ones, I believe ] (Keep a bow with you too, for arrow shower)
Orlean's shield [ Thara frog Card ]
Wool scarf [ Raydric Card ]
Tidal Shoes [ Maytr Card ]
Int Vesper Cores or Earings  [ some int card that I can't remember ]