Some of the challenges one encounters with denim and pleat curl stems from a number of factors. It's hard to find denim made from 100% cotton, a lot of it will have some lycra, giving it more give and stretch, it can be a challenge to sew and you may have better results piecing the kilt in 60" widths and splicing the selvedge ends to get the desired length of the kilt rather than having the selvedge as the hem. If the pleat face is too wide and there isn't enough pleat depth the pleat will curl. If there's too much taper from waist to hip that will also cause the pleats to kick out. (Adding more pleats will ease this problem) Then there is the issue of too many pleats and you have bulk and you will need to cut away the excess material.
I have found that a pleat face between 1.25" and 1.5" and pleat depth of 3" (6" of fabric) work rather well. There is no need to cut out pleats. If you sew the fell and pick up the previous two pleats there is no need for steeking and your pleated section will be very strong. Most sewing machines will be able to sew through this thickness. Denim can be hard on needles so have a number on hand. Start with a fresh needle when sewing the waistband.
Reverse Kingussie pleating will lie flat if proper measurements are taken. The issue with off the rack kilts is in most cases if the hip is bigger than the ratio determined by the manufacturer the pleats will turn out.
For sewing close to the edge of the fabric you can get a guide that is magnetic, works like a fence on a table saw.