I'm also looking for a place to level up.
My main team is lv 70-72,and i just got some good beating by Dimsa and Diabolos at Lhusu Mines...(they are both VERY annoying when they have very little energy left)
The problem is that atm i can't have access to the Henne mines area you all seem to suggest,so i think i'll try Giruvegan or Pharos.

Btw,is there a strategy to beat Disma (i don't have holy atm)or just need to level up?