Whether you pleat to the sett or to the stripe with a box pleat kilt largely depends on the size of the sett. If you want the reveal to be 2-3", you need a pleat every 6-9" (3x the pleat reveal). If the sett is somewhere between 6 and 9", you pleat to the stripe. If it's much less or much more, you'll have to pleat to the sett.