I guess this depends. Probably will have to try both and see where you manage to create a better business. If you want to have pre-made accounts you will most likely have to make the most popular ones. NMZ, BF etc. ready, started pures and so on in order to be able to sell them easily. They will go for less thought than accounts by the order since probably people would want something not that main stream. Specific quests, skills, diaries, so they pay more. And providing services when you skill on the customers account is most profitable way to go, but in this case botting is out of the question