Using SO's or Level 25 common IO's for enhancing:
Has to Hit? 1-2 Acc
Deals Damage? 3 Dam
Heals Damage? 3 Heal
Resists Damage? 3 Res
Dodges Damage? 3 Def
Costs Endurance? 1-2 EndRed
Gives Endurance? 3 EndRec
Status Effect? 3 of the appropriate Mez
These are good baselines for ANY build. If using set IO's, making sure that you're enhancing to roughly those equivalencies will be solid, and you get the benefit of set bonuses (potentially).
Specific to /DA - Make sure you have -KB protection in there, at least 4 points, preferably 10-12, best case overall is 20. You can get these from IO's, set bonuses, or Acrobatics from the Leaping pool.