The narrow pleats have less depth inside than the wider pleats. In either case I make the pleat depth equal the outside width of the pleat. (i.e., the 2 1/2" pleat has 5" of fabric inside).

I do this for a reason: It makes the inside of the pleat line up with the stitch line at the top of the previous pleat. This makes it easy to hand stitch the top inside of the pleat, which I do before trimming the extra fabric out of the top of the pleats. Making the pleats any deeper interferes with this process, and it tends to let the pleat droop more.

Not all kiltmakers use my approach for securing the tops of the pleats, but it works for me.

I've done the narrow pleats for a few customers before, whenever someone asked. I figured it was time to make it a "standard option"!