I will not ride Star Tours (did years ago, very unpleasant) or Mission Space (small space not going to happen) .... period. The Simpsons ride at Universal was absolute torture years ago and will NEVER happen again. But, I wanted to experience FOP. It is different....a few things that helped me were that I didn't feel terribly closed in, your vehicle moves independently (as opposed to feeling like you are in a moving box) and air blows on you. I took bonine the morning of our FOP FP+. While riding, I made sure to breathe steadily. I also focused on distant points throughout the ride.....as I "flew" past one, I would pick another. Afterwards, I felt mildly carsick....which faded quickly with a Night Blossom and pineapple spring roll from Pongu Pongu.
While having to work at not getting too sick must mean that I couldn't appreciate the ride as much as someone who could just let go, it was worth it for me.
That said...I could totally understand not wanting to take a chance...everyone has different triggers and levels of reaction.