Iceblossom

In the horizontal layout, remember you are working with parts of a yard in the cut direction, but the WoF in the other direction. Depending on how wide/long you need it is 7-9 yards.

So when you have almost enough with the two WoF sections, you can cut a an additional yard into three pieces for that center piece. That gives you (3) 12xWoF (we'll say 40") so 12x120" plenty long enough. It's a good place to piece in a label! That would be the 7 yard option.

But if you need it wider than that and you want the fewest seams, then it is an additional 3 yard piece and you will have a long usable left over for another project.

I typically press open, if you send to a long arm person ask them what they prefer, I believe most are open as well and I use .5" seams for the backs, not the standard .25".

This is quilting but it is also geometry and it is actually fun and there are many ways to do stuff. Maybe someone who does the slice on the diagonal technique will weigh in and help us, it's a great way of getting just a few more usable inches of fabric out of our rectangles. I don't do it, I piece in all sorts of stuff instead, but it's a great technique for when you are otherwise just a couple of inches short on your fabric.