I don't have experience with royal icing...it is strong enough to support the weight of the bows? How quickly does it dry? Should I insert toothpicks/skewers in the knot portion as well? Should this be done on location or can this withstand an hour of travel time to the destination?
Place the toothpick where each bow will be positioned. If you make the royal icing think enough it will hold the bow and dry fairly quickly. I would do the bows on sight.