The method of putting your heel on the pedal to determine seat height is dependent on the depth of the heel of your shoes. For example, mountain bike shoes typically have actual tread at the heel, whereas road bike shoes typically do not. In other words, I wouldn't use that method.

Also, I have not heard of anyone recommending knee angles as low as 5 degrees. Most often I have heard of angles of 30-42 degree at BDC (For example, if I recall correctly John Howard recommends 38 - 40 degrees).

Steve