I have the Grace Sr-2 frame. It only has two rails...take up and feed. Mine said quilting space was 102" but considering the machine takes up space, it's actually less than that for me. I do mostly lap quilts and baby quilts with a bed size thrown in once in a while. Consider how often you would actually quilt a king size. For me, I save so much money quilting my own stuff that if I were doing a king quilt Id send a good LA to send it to.