As for my experience with publishing through Amazon...a bit of a headache because I had never self published before.
The biggest problem was formatting. Because of how limited Kindle publishing is, it is not exactly what you would call "playscript friendly." You cannot use tabs, etc. So, regretfully, that prevented me from using the proper format that is widely accepted. From what I learned, there are companies out there who will do a near perfect snapshot of your playscript for Kindle reading but that comes with added cost. So to do it on my own, I had to change the format completely to make it an easy read. Took several tries and few choice words later until I got it to work.
I am sure there are easier ways of doing it. But you live and learn. I'll be posting soon about the play itself because it has an interesting history.