We visited T-rex the first week of Dec. There was no wait for a table. We were so excited. We arrived around 7:30 after a day at Animal Kingdom. When I told the waiter how surprised I was that we were seated so quickly he said that they usually start thinning out right about then. We were told that we could explore the restaurant while we waited for our food. DS wanted to build the dino at that time, but I had him wait until after we ate. I felt that he would enjoy it more if he wasn't rushed. Even if you aren't as lucky as we were then I would say do not build the dino while you wait unless the wait is an hour. (You have to choose the dino, build it, consider accessories, print a birth certificate, and purchase it.) BTW the staff at both T-rex and Build A Dino were very friendly and accomodating and I'm sure they can steer you in the right direction for the wait time and crowd level you encounter. We had a great time - hope you do too!!!