Need help in designing quilt with different size blocks

[Davidsgirl08]

I did this but I had an alternating block that measured 6 1/2 inches. I did a memory table runner for my mom. I didn't pre measure the pictures I just filled in with fabric. Some had 2 pictures and I did like a four patch 2 pictures and two HST blocks some had thin sashing some had thick. I varied it and in the end I had 6 1/2" blocks to put together. I attached the picture I'm still hand quilting the border but maybe that will help you a little. Some of the others have blocks under. Rachel