I have never flown Frontier before. We are looking at a flight DTW-DEN-SNA in Feb, with Classic fare. My husband is very tall and needs the stretch seating. With UA and Delta those seats can be reserved at the time of booking (exit rows for Delta with Medallion status). F9 flights are much cheaper, but, as I understand the website, the stretch seating cannot be reserved until check-in with Classic fare. If we check in 24 hours ahead of the flight time, are those seats likely to be available, or already taken by summits/ascents? We would not want to fly F9 if he cannot get the extra legroom.