Berry
I find the kilt a warmer garment than trousers in the winter. I live in the great white North and wear a kilt year round. I wear my cotton or hemp kilts year round and find they keep me rather warm no matter what the weather. I also have a wardrobe of leather kilts and they are nice and warm in the winter and surprisingly cool in the summer.
In your argument above what is the actual feelable degree temerature wise. I would think for the average joe it would be hard to tell the .5 degree difference. between the pleating arrangements. Also it may depend on how many yards one is confining to the backside. An 8 yd 11oz may be warmer than a 4yd 16oz or 4yd 22oz. With all due respect methinks you are thinking too much.... I think you will be rather comfortable in a 10oz cotton kilt as a 16 oz wool kilt if it contains the same amount of fabric.