If you are not expecting to have your preferences changed, they probably won't be. I believe that for the study participants they explicitly recruited older, religious people with no previous psychedelic experience. People much more suggestible to the power of magic. What is more likely for you is more of a "huh, it's kind of neat that my brain also functions like this."

I think that for a rationalist to have permanently changed beliefs as a result of a psychedelic experience it would have to represent an improvement in one's rationalism or personal utility function. If you spend the trip mediating on optimizing your preferences, then you're only going to improve them. Most likely, nothing will change, but there is always the possibility that you can be more rational.