Josh,

That's great that you are trying your hand at kilt making. I look forward to seeing the results.

Historically, the smallest number of pleats I've seen on a box pleated kilt is 6 (it's actually the MacDuff kilt, c. 1800, that we have on display in the museum). And, in my own kilt making career, 6 is also the smallest number I've made. I'd say on average I get between 8 and 10 pleats in a kilt, but up to 12 is not unusual. Of course, for larger men the number will be higher.

I find that a pleat width of anywhere from 2" to 3" is ideal. I've done larger pleats for larger men and they don't look bad because they are proportional to the size of the garment. I think the largest I've done has been around 3.75" or 4" wide. I wouldn't go this wide on a slimmer man, though.