For the first time, I am going to quilt one of my tops. This one is a baby quilt 45x60. How do I know how much thread to buy to do this? Next, I will be doing twin sized quilts and want to get enough thread, but not way too much. Please help me figure out how to calculate the amount of thread needed for the size of each individual quilt. All quilt tops are my own designs so no patterns to follow. Thanks ahead of time for any advice.