I wouldn't be so quick to discredit thought experiments. I am sure there have been some useful though experiments in human history. Also the understanding of free will is not entirely based on thought experiments. There have been many experiments carried out in labs around the world. Coming to your point about deciding which movie to pick, do you have any idea how you picked the movie that you choose. There were probably 3 or 4 movies that came to your mind and then you might have a mental debate between the ones you thought of and then picked one. On what basis did those 3 or 4 movies come to your mind and how free are you to choose that which did not arise in your consciousness.