The splits sound fine, but I don't think you can get away with 38" for the apron and underapron. Each is 19" at the hips but will flare at least 1.5" on each side. So, you'll need a total of 22" for each, for a total of 44". With 20 pleats (180") and 238" of fabric available, that leaves only 58"/2=29" each for the apron and underapron. That's just barely enough for a deep pleat, with nothing left over for the fringe edge facing. You might need to cut the number of pleats a bit.

But, if you do, you might wind up with a pleat that has to be big enough that it will "leak over" into the next white stripe on each side (kind of like the one in your test pinning on the very left that has the ghost of the next white stripe on the left edge). I don't think you want that, because it will be very hard to do perfectly and might also look odd with a little white at the edges of the pleats. So, again, you'll need to do a little testing. These are the pleasurable frustrations of laying out a kilt!

You _could_ alternate setts, but I guess I'd have to say that trad kilts are either pleated to the sett or to the same stripe, but not alternating ones. Doesn't mean you can't do it, but, to a kiltmaker, it wouldn't look "right".

Personally, I think the best solution would be to make a few of the pleats single-sett depth, as you suggested in your post. I did the reverse once, when I had a kilt that had a huge A-B-A-C sett that someone wanted pleated to the sett. If I had used the full sett, the max number of pleats I could have gotten would have been 14 pleats! I could "cheat the pleats" on almost all of them by going over only 1/2 a sett, but about every 6th pleat, I needed the full sett. So, I wound up with a respectable # of pleats. It looked a shade odd on the inside, but no one looking at the _outside_ of the kilt would ever notice.

I also made one once that had a very small sett but someone had given me 7 yards and wanted all of the tartan in the kilt. It was too much tartan for pleating to the single sett and too little for pleating to the double sett. So, I think I alternated shallow and deep pleats or something like that. Again, it wasn't noticeable unless someone was walking and you looked really carefully.

Gonna be a nice-looking kilt when you get it all sorted out!

Barb