I wouldn't gamble with it late then, as that's on the cusp of the big crowds. I'd go for 15 minutes before the first day and then adjust for the second day depending on how it goes - figuring the second day will get more crowded but the 7am time will scare some off. Keep in mind too that it could be the same park with the early hour both times. Also, note that walk from the hotel can be faster than the boats sometimes. We stay at RPR and once beat the boat by at least 10 minutes.