For FOP, if you start to feel sick, close your eyes. I can't do "spinny" things anymore very well. But I have days where FOP doesn't bother me at all and there are days when it does. I gave GotG a try twice. First time I had taken Bonine in the morning, but we didn't end up doing the ride until the evening. I was uncomfortable after the ride, but I recovered shortly after. The second time, I took the Bonine in the mid-morning and we did the ride in the early afternoon. I faired better the second time around.
The ride is smooth, but fast. There is a vortex. The music is loud and if you can distract yourself in the music a bit, I found that helped a little. They really did do a good job with this ride (except some of the pre-view, imo), so I think it is good to experience it once. You will only know how you react to it if you ride it.
Also, I kept my eyes closed for most of the first ride. I tried opening them a little more for the second ride. I'm not sure that made much of a difference.
Good luck!