The remaining ten units are tucked beneath my heavy set of Webster's Third Edition getting nice and flat after being ironed. This is a trick I learned from Sally Collins in her Precision Piecing video. Whenever I have fabrics that resist being ironed, you know, the kind that thinks it needs to go right back to its original shape no matter how hard you press? I place it, still hot, under my trusty Webster's and let it cool under there. Webster's is very convincing!
Enjoy the process!