Under Apron On Modern Kilts

[Steve Ashton]

The Utilikilt are who started the current thing with narrow aprons. Those who copied the UK have almost universally kept the narrow apron. Some makers have changed the under apron in some small way or another like UT.
In general, if the garment has a narrow outer apron it will probably have a corresponding narrow under apron.

And for the record a kilt made in the traditional manner will have aprons which are slightly greater than 1/2 of the wearers waist circumference. A traditional style kilt will also have aprons which are wider at the bottom than at the waist. This is a design feature to allow the side edges of the aprons to hang straight down, vertically, when viewed from the side and not gape open.