I try to make my ADR about 1/2 hour before Wishes begins, so there is plenty of room either way if nothing is available at the 1/2 hour mark. Anywhere from 90 min before to right up till showtime is good for me.
The staff is very good about timing everything so that you can step out on the deck to watch the show.
I have never tried it, but I understand that even if you dine early in the evening they will allow you to come back to watch the show.
We have our ADR for after Wishes and were told that we could arrive earlier to watch Wishes from the balcony prior to our reservation time. I think if you call to schedule your ADR and let them know that you're trying to plan for seeing Wishes they can help you figure out what time will work best for the night you're going.
If Wishes is at 11 then really any ADR time that day will work because if you keep your receipt for a meal earlier in the day they also allow you to go back later that night to watch Wishes.