If there are meals you really want to try, definetly make a ps or you will be waiting much longer for a table. I usually make one ps per day for a restaurant I want to try. For us that meal is usually lunch since after that we usually head off for nap time. We have a 2yo DD. Her first trip to WDW was at 14 months and I did the same then, worked great. Dinner we usually play more by ear.
Gi