Take a large ball of playdough and squeeze it in your hand until it feels comfortable. Measure the "tube" of playdough that you just made, and make your handle that size. My handles come out to be 1" wide by 1.25" thick by 4" long. Sometimes I make a bulbous handle where it is 1" wide at the fades, then expands to 1.25" in the middle of the handle, then back down to 1" at the other fade.