It depends on what you're tasting! I cannot remember for the life of me when my tasting was (it was 11 years ago) but I went to my planning session by myself. This was back in the day when you could have less then 18 guests if you met the mins, so to do so I went all out on my menu. Plus mind you I tasted all 3 of my entree choices. Plus all the other courses (5?) And I actually ate the whole piece of grouper cuz I couldn't help myself (I'm the only one who got it, the fools, that was the best). THEN I tasted cake (and before that the dessert course I decided to drop in favor of just cake). AND my planner had them make up a LAYER. So I had this thing to take back to my room.
That night several members of a Disney group were all at the parks and I'd made plans to meet with them for dinner. I rolled my way there and picked at a salad.
So basically what I am saying is, I would either make very late plans at a light restaurant or maybe just wing it with quick service or room service later if you get hungry.
