Sorry Rachel, didn't get any pic of your diagram, but I think I can imagine larger blocks on the back.
I'm not familiar with K3n's no sew backing with QAYG - which is probably why I came up with my solution. It still needs sewing on the back, but its on the batting, not the backing fabric. I have one boarder done and ready to attach, and the second border sewn together, but not tidied up on the back yet. I'm not going to be doing much today, I have a dental problem, and need to get an extraction at lunchtime, Ugh!
Is it time for week 23 yet? If so, shall I post it?