Jim Forbes replies: Using the Fibonacci sequence will result in the most esthetic graduated sizing. It is easy to use for almost any project by just selecting the area in the sequence and moving the decimal point.
Garrett Hack replies: The Golden Rule is a 1:1.6 relationship between the width and length—not useful for sizing graduated elements. However, there is the Fibonacci sequence that you might find helpful: 0, 1, 2, 3, 5, 8, 13—although I never have.
Draw what you have in mind full scale if you can and play with the relationship of your boxes—you’ll get it. Sometimes just adding 1/2˝ to your smallest box and that again to next and so on makes an interesting graduation.