I looked at this site when I was researching fabrics for my line.

First; The Wool blend fabrics they offer are not denim. They are Twills.
Twill is any fabric that shows a prominant diagonal line. The are woven by passing one on the vertical threads under one horizontal and then over one/two/ or more horizontal ones. Denim is in the Twill family of fabrics.

Second; In true denim the horizontal and vertical threads are different. One is dyed and the other is plain Cotton. Look closely at your jeans.

Third; Denim is a terrible fabric for Kilts. Again, look at your jeans. Along each stitching line you will see a pucker. All Cottons, and Denim in particular, will show this pucker. Because of the different threads in Denim, this pucker is VERY pronounced. After a few washings the pleats will begin to shorten. Sometimes by as much as two inches. This puckering will cause the pleats to fly out the sides and appear to be imitating a tutu. Only repeated Ironing and stretching of each and every pleat can keep it under control. Denim is not a soft fabric. The yarns are spun very tightly. It was designed to be rugged, not to drape.

Fourth; BEWARE of any fabric with even the smallest amount of stretch. Stretchy fabrics stitch just fine in one direction. But a stitch line in the other direction will cause scalloping. On the fabrics I tried, this scalloped edge caused every pleat to look like a ladies Vicrorian collar.

my two cents worth.

I still get requests from customers for denim kilts. And I try to explain that just because a fabric is good for one garment does not make it suitable for a kilt.