It was just brought to my attention that the dimensions for the base piece of the basket are incorrect. They should be 5-1/2" x 5-1/2", not 4" x 4".
If you have already cut the rings, you can use the remainder of the base from the original blank by sanding off the wedges from the underside. It should match the bottom ring perfectly. If you drilled a small hole in the center for pattern placement, you can fill it with a mixture of glue and sawdust and it will pretty well disappear.
Sorry for the error, but sometimes they slip through despite many layers of proofreading.