I have the same set up. I had been quilting for several years before I was watching a longarmer with a 36" machine. I noticed that he did the first row left to right and the second row right to left. I asked why and he said it was just like when you sew strips together, if you don't alternate the direction of sewing, the whole thing comes out skewed with one side shorter than the other. I had been quilting always from the left side.