I'd start with a 150w HPS personally, it's 100$ and should get you > 5 ounces. Air needs to move in and move out constanly doesnt have to be a huge amount, leaves should be contantly slowly waving to breath with little fans inside. (Not as importnt when they're babies maybe too much wind is actually bad) I'd go basic soil from walmart, peat moss small amount of fert or whatever and some buffering agent, any peat based simple potting mix is great then GH 3 part nutrients, start in solo cops, dont water until pretty much completely dry then move to a pot only twice as big or so then repeat. If they are not growing super fast and stretching out tall and wide you are watering them too often, i wouldnt even feed them till they are 6" to a foot tall, IMO perfect starting kit for a first closet grow.
I started with a 1000w HPS cause I was super cool lol I hadve a 150w HPS and it's incredible, I'll post some pics later of what that little thing can do.
This is just my opinion there are 1000 other ways to do it maybe even better, just what I came to.
Good luck! Don't give up and don't settle... if something looks not great this is the best place to ask for a second opinion.