Alisa Golden has several posts on her blog about the fishbone fold. The first is a variation that has an even fore edge. In her picture below, the results from the original instructions are on the left, Alisa’s variation is on the right.
Alisa thought the even fore edges make the book more plant shaped. Below is a magnolia she saw and the book she made in response to it. More examples here.
I have to give that a try. It looks interesting!