In several other threads there are responses about cutting binding strips and there are always several different ways/widths. How do you determine how wide to cut the strip? Do you always use the same width of finished binding? THESE questions relate to double binding.
While I generally use 3/8 inch seam, I do vary the width depending on the size of quilt and look I want. A trick I was taught was to determine the finished width of binding I wanted then multiply that by 7 to give me enough fabric to sew the second seam by hand. Since I do everything by machine, I usually multiply by 8 to give me enough to work with for the 3/8 seam.