My DH & I often share an appetizer and entree for lunch, especially if we want dessert. In my experience, the portions are quite large even at lunch. We both do better if we share as we are not accustomed to eating a lot at one time. But it's nice to have an appetizer and dessert and I am comforatble ordering/eating those if we share. Otherwise it's just too much food for one time!
When we eat a late lunch, we seldom have more than a light snack for dinner. FWIW, we've found the prices to be less at lunch and if you have an AP/PAP, you can even get a 10% discount off lunch prices at the EPCOT sitdown restaurants.
Enjoy your trip!