Help! I am sewing a quilt that has a hst's and a nine patch, every other one. It is a king size. My problem is the rows are starting with a hst and ending with a nine patch. This fits perfect on the bed. Or should I be adding another square to have the row end the same as what I started with in that row. If I add another square it will hang over the bed about 3 inches on each side. Is there a rule of thumb on this?