Make a sample square quilt square to practice the stitch width. I keep my sample by my machine with the setting written on it.The sample is about 7x7 inches.
I use 2 1/4 binding. Sew it on the back of the quilt and bring to the front. One tip is to put a straight pin right into the seam allowance on the back and poke to the front. You will "see" where that back line falls.
If I use binding that is 2 1/2 inches I use a 3/8 seam to sew the binding onto the quilt. When the binding is folded to the front, it is more even.
I love using flange binding too.