We were at the park on July 4, 2-3 years ago. At opening, my husband got in line for RSR and I went straight to the FP machine. By the time I reached him with the FPs for a later ride, he was waiting for me at the entrance to the RSR. The line was moving quickly stepped aside and waited until I go there. We were on the ride in less than 10 minutes. Our FPs had us returning around 10-11 if I remember correctly, we went back then and rode it again. I had heard that it was really fun at night as well so we watched for evening FPs to become avaialble, I think we got them around 11am for an 8pm ride. So...I would expect FPs will still be available if you arrive at 10am, but you'll likely only be able to ride it once unless you want to stand in line.