I’ve been making 8.5″ square crazy quilt blocks with backing. The backing is new for me, and was suggested by my older kids and a book. Using muslin to stabilize does add stability, but it also decreases my freedom somewhat. I liked the non-backing squares because I could “trim as you go” — sew a seam to join, then trim the excess. With a backing, you just can’t work that way.
Plans are to make the wonky houses from earlier into 8.5″ squares by adding to the edges or trimming the edges. This means that the houses will have a lawn! Maybe I’ll end up embroidering a tree or two as well.