I think a smart thing would be to get a bunch of outland herbs together also. From what I understand there are different "levels" of herbs. Milling a certain level of herbs will yield you that level of ink. I would look into getting a bunch of the cheapest herbs together (Felweed/Ragviel). I am not sure if there are a couple different levels of outland herbs or not. It would be a nightmare if you had to mill a bunch of fel lotus.

Wowhead has the following information
Herbs
Name/Level
Fel Lotus 75
Mana Thistle 75
Nightmare Seed 73
Nightmare Vine 73
Netherbloom 70
Ancient Lichen 68
Flame Cap 67
Ragveil 65
This is just speculation on my part. I am not a beta tester!!!!!