I'm hoping someone can shed some light on this.

I was recently studying thread counts due to wanting to design my own family tartan. I have several kilts and of those is an 11 ounce tank and a 13 ounce tank - both made by Loch Carron mills. In the MacGregor green and red tartan, there is a white stripe bordered by a black stripe. In the 11 ounce tank the white strip is 6 threads wide and the black stripes are 4 threads wide but in the 13 ounce tank the white stripe is 8 threads wide and the black stripes are the same (4 threads wide). I was under the impression that the thread count doesn't change regardless of the weight of the tartan. I thought the weight of the tartan is dictated by the thickness of the thread used to weave - thicker thread in 16 ounce than in 13 ounce. Was I wrong in this assumption?

Here is a picture of the two kilts - the 11 ounce on the left and the 13 ounce on the right:




I have an ebook of tartan thread counts (PDF) for hundreds of tartans and it states:

MACGREGOR
-----------------
A 24 green
8 red
8 green
2 black
4 white
2 black
8 green
8 red
24 green

B 64 red
-----------------
152 ends.
How does one decipher these numbers? How does thread count work? Does it vary with the weight of the tartan? If it varies with the weight of the tartan, which weight of tartan are these thread counts for?