I am sure tht others with more experience than I will chime in here, but I do know that there are box pleats and then there are box pleats. Matt Newsome specializes in making box-pleated kilts from four yards of tartan. The pleats are fairly wide and few, but the pictures I've seen of these kilts are very nice indeed. They are reported by wearers to be lighter than a conventional 8-yard knife-pleated kilt and are quite handsome but decidedly different.
At the other end of the spectrum is the military box-pleated kilt. These are pleated by folding the pleat back on itself, so that from the hem end they look like a box pleat on top of a knife pleat. Again, a different look from a conventional knife-pleated kilt and quite heavy by comparison.
Somewhere in the middle would be Lady Chrystal's double box-pleated kilt, another attractive option.
A search of "box pleat" will, I am sure, yield a plethora of threads on the subject.