Sashing is going on quickly and easily now, but a lot of effort went into that.
I always learn things in these mysteries. Sometimes what I learn is more about me than about the quilt and we have quite a bit of that but so it goes... Quilting-wise I had one of the Aha! moments (or maybe it is a d'oh!) and an improved skill.
I made this project needlessly complicated with my layout. Not that it really matters, but I had everything placed so the same fabric didn't touch and it was important how the sashing went together. I do fairly often work on things that do have complicated layouts and have ways that work for me. Some people have that nice design wall, that is still not so much an option but I do have the design bed

We will be getting a king for the main bedroom (I will probably want to use that instead) but the queen will go into the guest bedroom. It is absolutely amazing to me the number of ways I can go wrong, from what side of the block does it go, and which is top or bottom. And sometimes the whole block drops and pieces scatter.
Short form: I can color code the little clips and mark what pieces go to which portion of the block. Maybe pictures will help?
Picture 1: From my layout, I put the pieces in place with clips.
Picture 2: Laying out to sew -- part of the issues with this project was working in 3 parts was awkward to sew
Picture 3: Before sewing, Clips added to mark where pieces go -- they are out of the way of the sewing.