I also finished the single dart skirt sloper from Building Patterns The Architecture of Woman's Clothing. I used the suggested 20 inch length and a high hip of 4 inches and a low hip of 7 1/2 inches, though the suggested is 4 1/2" and 8 1/2". I'm just under 5' 4", but I have a very short torso for my height.
The back is actually better than it looks from the waist to low hip. I didn't do a zipper, but just used safety pins for this opening because while I've been adding more zippers to my stash lately, I'm still getting a feel for what to stock. The book does have you make two measurements for the right and left side to the ground, but it doesn't have you make those same measurements for any of the other measurements, like the waist to knee. I'm going to add 1" to the right side and the center back of the left side.
I'm planning on making these changes and another muslin before moving on to the first variation which is a yoke skirt.