Generally speaking these granny squares were all made for a specific purpose and have a size that may or may not work as preferred. As a general rule the following fits well for size increases:
Naturally a person can use any configuration of the right-sized stitch in keeping with the original design for size increases.
These are four blocks I designed for my 1960s-colored bright granny blanket, then recrocheted in a different color for each round to see them better.