I would probably look for a reservation between 8:00 and 8:30 pm if you wanted to see Wishes. I generally allow about 2 hours for a three-course Signature meal. If you aim to be seated about 90 minutes before the show, there is a good chance you'll be between entrees and desserts when it's time to go out to see the fireworks. Otherwise, if you're looking to try and get a window table (they do take requests, but they will not guarantee that a table will be ready before the start of the show), I would aim for a reservation that is at least two hours (probably closer to 2.5 or 3 hours) before the show and plan to eat slowly.