fleece has a direction with more stretch than the other direction---if you are piecing the fleece make sure you have the stretch going in the same direction- you dont want one piece to have the stretch horizontal-the other piece vertical.
i've backed lots of quilts with fleece & i long-arm- i've had salvages on the sides & i've had them vertical---you should check with *the long arm quilter* you are taking your quilt to & ask her if she has any preference---make sure she is comfortable quilting fleece backed quilts.