I have done it a different way. Fold the fabric on the sides in when you put it on your frame and make it fit the frame with the excess folded. Then I quilt the parts that I can get to avoiding the folded in fabric. If you are on a longarm you should be able to quilt everything except for the sides. Then take it off the frame and turn it 1/4 turn folding in the new sides and quilt the areas that you weren't able to do the first time. If you are not on a longarm this should work also. The time it takes to reposition it on the frame should be less than the time to get the borders on and quilt them later.