I've loaded my quilt backing, and have it straight, rolled it a few times to make sure everything is straight, but even though I have rolled the backing a few times to get the fabric to behave, it still sags on the right hand side for the first 16" or so...have any advice or help what to do...will it be ok to just put the batting on and top and start to quilt it? my table and everything is level so it's not that...I know that I was told to roll the backing several times to get the fabric to behave, but my heavens how many times do you have to do this....