I just measured the harp on my Bernina 530 and it is 7.25 inches from the needle to the arm. I have done a king size quilt on it and several queen sizes. For me the secret is to stabilize the quilt vertically and horizontally by stitching in the ditch along the seam lines of the blocks. Then, when quilting, I only need to be concerned about one block at a time. Then, because the blocks are stabilized I can work the outer blocks first. Then I put the binding on the quilt so I can cut away all of the excess stuff around the outside of the quilt. It greatly reduces the amount of bulk to deal with.