I would recommend cuting backing even with top, especially for your first one. I cut ALL my binding across the grain, only time I use bias is for curves (like a round potholder). I cut mine 2-1/2" wide and fold in half with raw edges together, this will give you double binding on the edge were it will fold over the quilt, I believe this is called a french binding. A lot of the "older quilts" were done with the binding raw edges folded to the middle, which worked great except it only gave you a single thickness in the middle where you need the strength. IMHO