Little confused by your ? tkhooper. Do you want to increase the size of 36x48 to make it longer for a window covering 36x66. Sashing advice would be to keep them the same colors, not necessarily same fabrics, i.e. use some cream scraps for the sashing.
I used the red fabric bought in January. I started with this. The 9P's were all made from 1" wide scraps as trimmings from larger cuts or backings.[ATTACH=CONFIG]513842[/ATTACH] I found an antique quilt online as inspiration....648 9P's later [ATTACH=CONFIG]513843[/ATTACH]