Quote Originally Posted by M. A. C. Newsome View Post
*** what Paul said. The threadcount of the tartan is not hard and fast. It is meant to give an idea of proportions. So long as the proportions of the pattern remain visibly about the same, you can modify the thread count as needed.

To give a very, very simple example, the thread count of the Red & Black MacGregor tartan (aka Rob Roy) is often given as K=R. This means that the black threads equal the red threads. Now it doesn't matter if you weave it at K20 R20 or K40 R40 or K102 R102, visually the tartan pattern would be the same, just on different scales.
And I only thought that the fabric weight was what determined the sett size i.e. the heavier the cloth the larger the sett. I suppose my preference would be for a larger sett to better show the pattern so a larger sett for a complex pattern and smaller for a more simple pattern. I do like the large sett on the example that started the thread.