I am also a hand quilter and have made several log cabin quilts.
My quilting solution is to quilt circles over each motif. That way
you do not have to battle every seam. For me, putting circular designs on square patterns and square designs on circular patterns is just one more element of contrast.
My son has the first quilt I did this with 25 years ago. It has been washed once a week during that time and not a stitch has come loose!
Whatever you do, it will look gorgeous. I really love your color palette.
Marveen
in Sunny Tucson, AZ