So I've decided where I'm to order the tartan for my kilt from, and there is only one thing that is sticking out at the back of my mind (aside from the hefty price tag, of course).

Do tartan mills use a set array of colours for certain ranges (some for Weathered, some for Modern, etc?), or do they weave custom shades based on individual orders? I am aware that two mills make my tartan in Ancient, but I would be interested to see it in Weathered, from DC Dalgliesh. So would I be able to order a swatch at a small fee, or would I be reduced to starting at yarn samples if I want to get an idea of the colourations?