We were there June 20-23. We wanted to ride RSR at night so we stalked the app and booked a 7:40-8:40 FP at about 10:30 am. We returned at about 8:40 and waited 20'ish mins in fp line so we actually got on at about 9pm. It was awesome!!!
We also wanted to ride IC at night. We only had opening day so at about 12pm, I found fp for 7:30-8:30. Returned right at 8:30. Also about a 20 min fp line so getting on just before 9pm. Also really great!
So, again, our timing for IC was on opening day...my guess is that may be off a bit for regular days. Also, we are a family of 6. YMMV if you are a smaller party.