Leaking issue is almost always wicking problem. Too little cotton will lead to leaking while too much will lead to dry hit. If you are talking about aromamizer with velocity style post, then you are in for easier time of building as the deck is quite spacious to build along with the simple velocity styled post.
Just experiment with your wicking. There are many YouTube videos on different ways of wicking too. Don't be scared of leakage. It always happen to newbies.