when you start in the middle you need to go in both directions- doesn't work to do all the verticals- then the horizontals- you need to do a vertical line- then go do a horizontal line-
birthing the quilt does cause it's own set of problems- if you plan to quilt afterwards- it is a better method for tyed quilts.
when you machine quilt the backing/batting needs to be larger than the top- it is like embroidering or doing applique= the stitching process (draws up) the fabric- that's why we cut our embroidered/appliqued blocks larger- then square up after the stitching is done.
as you quilt the top will be (drawn up) in the same ways...so after quilting is when we square up- trim the edges.
it's not impossible to quilt it after birthing it= but it takes alot more work= so if you thought that would be easier???sorry-
it's easier to just quilt it then bind it.