I cut my binding on the bias - and I do baste the edges together before putting the binding on the quilt so that it lays the way I want it to. Otherwise one layer would shift on me. I might consider gluing the edges together, though, instead of sewing them together with long, shallow, zigzag stitches.
I DO NOT press the binding in half - because I believe that the final fold shifts a bit as the binding is turned twice - maybe only a small fraction of an inch - (maybe the difference between a 1/4 inch seam and a scant 1/4 inch seam)