I would give yourself about an hour if you preorder. Our took a bit longer coming out than the staff seemed comfortable with. Two different people came by (without prompting from us, we were just sitting at an empty table with drinks only) and checked our tickets, apologized for the wait and said it would be soon.
We were probably there over an hour, but that was also because we ate slowly, visited, took in the sights, etc.
I really like eating there. I like the theming so much.