I wear 4 yard box pleated kilts year round. The X Marks tartan is a 15 oz, if I remember correctly, which is a heavy weight. I, for one, never have any problems with the kilt acting up in a strong breeze, and temperature-wise, there is no difference between a 4-yard box pleat, and 4-yard knife pleat. (Though you will notice it is cooler than an 8-yard knife pleat!).

Aye,
Matt