If you are having a sit-down plated meal with courses, you should make sure all toasts are done prior to the main entre being served so your guests can enjoy their meal and so toasts don't interfere with meal services and dancing. If you are having a buffet or station-style meal, toasts need to be done BEFORE the first table goes up to the buffet. It is nearly impossible to gather guests and keep them quite enough to enjoy your toasts once they've eaten and are ready to party. Waiting until after the meal will eat into your dance time significantly.