attworth,

What you are seening in the description of these fabrics is only part of the correct name.

The word "Denier" refers to the thread count of the fabric. How many threads or yarns per inch. The more or higher the Denier number the tighter the weave. For example, the average bed sheeting is 300 denier. A high quality bed sheet may have a denier of 600 and I have seen 800 advertised.
That's 800 yarns per inch! Bedsheets with Deniers of 800 to 1000 are referred to as "Hypo-allergenic because the allergy inducing microscopic dust mites can't squeeze between the yarns.

The complete name of these fabrics is usually 600 denier PVC coated Polyester fabric. These are the fabrics currently used in windbreakers and athletic clothing and raincoats. The Polyester fabric is coated with a water repellent surface of PVC to keep wind and rain out.

I do not think these would be very good fabrics for a Kilt. Some of these fabrics do breath but probably not in the area of the Fell where there are multiple layers. The fabrics are also quite stiff in relation to their weight so swish would be minimal.

The only application I can think of where these fabrics would be useful would be in Paintball Kilts. The PVC coating would probably resist staining from the paint.