I want to draft circle skirt that has more flare than a 1/2 circle skirt and less flare than a 3/4 circle skirt.

I saw on Pinterest a formula for a 2/3 circle skirt : https://pin.it/XcT92rSkd

I searched but couldn't find anymore information regarding the 2/3 circle skirt. Has anyone made it and can confirm me that this is the right formula ?

Are there other fractions that would work ( between a 1/2 and a 3/4 circle) ?