I do something very similar; I wait until I'm at least 25 though. Nightmare cows give awful experience if you're under level 25. I once leveled in cows with a friend, I started at 25, he started at 24. I was almost level 30 by the time he reached 25.Zavior said:I kill norm baal as soon as possible(lv21).
Then nm cows till high enough.