I've done some thinking about the weight of wool blankets a kilts recently. I have two wool blankets about the same size, roughly 5'x6' and one is perhaps twice the size of the other, but not much warmer. The heavier one is tighter woven, and better for laying on the ground, and better for cutting the wind, but no warmer for its thickness under a nylon shell.

Kilt fabric tends to be tightly woven, and 10-18oz per yard for about 60" wide yards. That equates to 6-11 oz per square yard. A great kilt or belted plaid of 9 yards would originally by of 9 yards of 25-30" wide home spun, sewn together, so it would only be 4.5 yards of 60" today, and might weigh 3-5 pounds depending on the weight of cloth. I would also guess that the old homespun might not all be as tightly woven as plaid cloth used today, so they might have been a bit breezier by day and somewhat warmer by night by being loftier for the same weight. Not sure.

Hudson Bay Blankets weighed 3.1 pounds per point, and covered 96" by 32" per point, so about 21oz per square yard. A 3 point blanket was very common for winter and weighed 9.3 pounds.

Not sure where this is leading, but I gotta go. Cheers.