OK, let's go back to how the book describes things.

Here is just an idea you could try.

For a kilt with a waist of 39 and hips of 43 we figure out the splits. 1/2 of 38 = 19.5 and 1/2 of 43 = 21.5. So I would pick splits of around 20/19 & 21/22. or even 20/19 & 20/23.

The apron taper will take up the difference.

With a hip back split of 22 I would create 22 - 1 inch reveal pleats. These would then taper to the waist of 19/22=.863 or pretty close to 7/8 inch. (This is why I converted over and use metric.)

Pick up the first pleat and pin it so that your element is centered in a 1 inch width at the hip. (The center of your center element is 1/2 inch from the pleat edge)

Pin your taper into the this first pleat gradually to the 7/8 inch at the waist. ( The center element is now 7/16 inch from the edge of the pleat.

Now pin the second pleat exactly the same as the first. Don't try to pin the second to the first just duplicate in the second exactly what you did on the first.

then lay the first pleat on top of the second so that the second pleat shows 1 inch at the bottom of the 8 inch Fell and shows 7/8 inch 2 inches down from the top of the kilt.

Stitch pleat one to pleat two.

Now, when you are done pick up pleat three and pin it exactly the same as you did for 1 and 2. Pin pleat two onto pleat three just as you did two to one. Stitch pleat two to pleat three.