Isn't the material 58 inches wide, normally they will buy 4 yards of the 58 inch material and cut it up the middle and sew the ends together to make 8 yards. If this is the case you only need 4 yards of the material to make an 8 yard kilt. It would be a good idea to note the width of the material on the site.

The modern patterns of the Campbell of Cawdor (also known as the District of Argyll) Tartan are very dark, if you are considering a kilt in this tartan, I would suggest getting an actual sample of the material. I have a kilt in this tartan, The green and blue do not show up very well in a photograph.