I have only done the back basting on one project, so I'm no expert.
But I would guess that you'd get smoother circles if you use the "yo-yo" sewing and starch method to prepare the circles. Those are some TINY circles. I think about 5/8" or 3/4" would be the smallest I would try with the back basting. Maybe not even those, as nice as you can get the circles when you use the yo-yo and starch preparation. I like a challenge, but mercy! Those are teeny!
