We went to one last October. We were served risotto and scallops. It was a lot of fun. We had a glass of wine and the serving size of the meal was about the size of the portions at the food booths in the World Showcase.
Same size portions you get at the booths. Not much, but several bites so you can get a good taste. They served on the same little plates, which are probably 5-6" in diameter.
You can get a good idea of the portion - the piece of paper is a regular 8.5 x 11 letter size.