I do not think it makes any difference where the seam is on the backing. and either does the quilt! 108 wide backing is great to use but often I want a color backing that better matches the front of the quilt. I like the idea of adding a coordinating stip to the backing to tie it in with front. I have made my own backing by sewing left over fabric to gether but I really HATE doing that! Making a square 108 x 108- what a pain!!!!!