I struggled with measurements (see photos of notes below) in an effort to be accurate. The outer edges of the center had to meet the measurements of the churn dash blocks. It was a challenge. In the end it seemed easiest to use finished measurements throughout then add 1/2" before cutting.
I don't know whether to add an outer border or not. Churn dash blocks are not very forgiving. There's 1/4" for stitching and that's it. If I need to square up the quilt after quilting and before binding, I won't have wiggle room if there's no border. On the other hand, I like the idea of a binding looking like a narrow border. Anyone have any experience with squaring churn dash blocks after quilting?
About the backing. In the top photo along the upper edge you can see backing possibilities. My husband votes for the red. When I told him I didn't have enough red for the whole back, he sounded disappointed. I suggested using the red and grey/brown, 2nd from the left. He had a ho-hum response. I have several pieces of dark green plaid that I could piece together for part of the back but I was hoping to take a really simple route. What do you think?
I hope you're making good progress with whatever you're working on.