When pleating to the set you want to replicate the pattern in the pleats.

Basically - if you have an 8 inch set and want one inch pleats, you fold 9 inches - so the pleat is 4 and 1/2 inches deep.

If you visualise a row of sets , labled A,B,C, etc, then you want to have the first inch of set A, the second inch of set B the third inch of set C and so on.

You can of course jiggle the measurements slightly so as to get the pleats to fall where they look best, as long as you maintain the basic pleating and measurement of the set.

I find that I want to slightly expand the set at the hip level rather than have the set perfect at the hip and the narrow it for the waist.

When you narrow it down to the waist, you can't then fit a waistband and match it perfectly all way round.

You could of course have a waist band only on the aprons where it would be a perfect match, and on the pleats take them up to the top of the kilt and have petersham ribbon on the back so the pattern appears to be continuous.

Sorry to add another conundrum, but it is something to consider if it would really annoy you to have a waistband not matching above the pleats.