My disk (runt) came with the nipple to the stem. In the manual it came with, it shows the nipple facing down towards the bowl, away from the stem, or the opposite direction in which it arrived.
Going with the manual and what
@nonamekevin suggested (I think), I flipped the nipple to face the bowl right from the start, never even tried it the other way. I've been using it with the nipple towards the bowl and I haven't had any issues so far with scorching or hot spots. In fact quite the opposite where I've been wondering if flipping it back to the way it was shipped will help me get more heat to the bowl.
That happened/happens to me sometimes, I think I get excited if I get a good first hit and then I automatically elevate myself to professional brick user status so I dont pay attention to the follow up hits and next thing you know I'm sucking butane.
I've been getting the best results when I remind myself to slooooow down. There's actually a lot to pay attention to - more so than I would have thought initially, and very minor changes seem to have a considerable impact on vapor.
Oh, I also think stirring is critical. I had a great session with it last night. First I finished off a bowl from the night before, I was able to take it darker than I ever have before, so that tells me I was doing a better job at getting heat to the bowl. After that, Two heaping scoops into the bowl, no tamping, just a little shake to even things out, and went to town. It may have been my best session ever in terms of consistency and vapor production. I stirred after every 2 hits typically. So I'm heading in the right direction! Didn't finish that bowl either, busted out my top shelf stash, forgot how good it was...