When I have made my filled cupcakes, I used tip 199, it is usually used for making borders and has a fairly wide opening. I use a thick straw, wood dowel, etc to make a hole in the cupcake then sort of roll it arond inside to make a nice hollow in the center, then I squeeze the filling inside. You can actually see the cupcakes begin to plump as you fill them, stop when you see them get plump or you will overfill them and would be very messy to eat. I have never had a problem with the size of the hole on top, I always cover it with frosting. I have made the Fresh Orange in cupcakes with orange curd filling and orange cream cheese frosting, they are delicious! You will not be disappointed.