RE: What is your height and your draw length?
The wingspan method was developed because of the disparity between height and draw length. So many archers at one time believed that their height was directly related to their draw length. This was proved to be so invalid that the wingspan method was developed.
While the wingspan method doesn't take into account varying shooting forms, it is a very good starting point and usually only has to be adjusted by +/- 1/2" to obtain something very effective.