What a beautiful quilt! Check out the warm and natural batting. The size it is, is the size you want to make your quilt. Buy it buy the package for the quilt size you need. It is actually cheaper that way. I get mine from Born to Quilt. (not affiliated) Otherwise, here is a chart I sometimes use.
Baby 45" x 56" Twin 66" x 96" Double 76" x 96" Queen 82" x 102" and King 99" x 119". I do make my Kings wider than 99". I have a 6'1" stocky built husband. This way he doesn't hog the cover. Silvia