For 2.5 inch wide binding, I use a 3/8 seam allowance. The binding will be close to equal on each side.
I put a straight pin in the ditch to make sure the seam will hit the binding on the back. Then hold the binding as I stitch it down.
I don’t iron the binding in half. That fold isn’t where it’s going to fold naturally when you wrap it over the edge of the quilt.
Most of the time, I stitch the binding onto the back and bring to the front. Easy to make the corners nice and keep the stitches straight.