It sounds like you've got a pretty good system in place already. The clarification I would make is that they must be completely defrosted the entire way through (not cool at all on the inside) before feeding to your snake.
Many people use the water method, but it's just not my cup of tea. On feeding day, what I do is pull the frozen rats I'll be needing out in the morning and set them on a paper towel or foam tray to thaw in the snake room during the day. When it's feeding time (I feed at night), and they've completely thawed, the only thing I need to do is heat up their heads with a hairdryer for a few minutes. Sometimes I use a temp gun to make sure that I've gotten them up to the ~100° F temp that a live rat would be. When they're nice and warm, I offer them up and have had good success doing so.