Jim,

That will work, but only for small adjustments. If you take inches out of the aprons, without taking inches out of the pleats, you will wind up with a discrepency. A 2" or 3" discrepency is no big deal (and depending on the build of the man, may actually be beneficial for the look of the kilt).

But 6" is quite a bit. In the cast of a kilt with a waist of 40", you can assume that the aprons are 20" and the pleats are 20". Taking in the aprons by 6" would mean having 14" aprons and 20" pleats -- in other words, the pleated portion of the kilt would come around the front. In order to really preserve the correct look of the kilt, you'd need to alter it, in the way Barb detailed, so that the aprons and pleats are 17" each.

M