The major downside of doing the quilting on the individual blocks is that each block shrinks a bit rather than the whole quilt. I also seem to have been a bot careless sewing on the strip at the bottom and it is quite crooked. Along with a bit of shrinking this has left me with nearly 1/4" of batting showing. I will have to be careful sewing the blocks together to make sure I catch all the raw edges.
They are left over because I only need three of the 12 that I got with the mini quilt kit to use in the big quilt. I completed the backing with a zip and now I am ready to bind the edges.