I have quilted 2 double-sided quilts on the longarm.....one was 105x115. That one did have a corner that had "grown" but it was less than 1/2 inch and the binding balanced it out. What I found important was to have the bottom (backside) border of the quilt at least an inch oversized on the side and edge of the quilt that will be the last pass of quilting. That way if you get a little movement, you can trim. I added a matching fabric strip on those edges and the little bit that it moved on that corner (so there was a scant seam where I had joined them) was hidden within the binding. E2E is the only way to go and measuring for every roll of the fabric. Loading was very time consuming....had to be just right.
Marilyn