The Poly/Cotton I use is advertised at 9oz. This seems light when compared to Wool Tartan fabric but it is a dense and firm fabric that holds it's shape well and resists fly-away very well.

I also build into my kilts A LOT of fabric. (Poly/Cotton is far cheaper than Tartan so the difference is not noticeable in the price.) There is extra fabric at the apron edges, extra fabric in the deep and reverse pleats, and extra depth to each individual pleat. All done to allow the pleats to "Swish" but heavy enough to avoid fly-away. Depending on your hip measurement you will have on average between 8 and 9 yards of fabric in your kilt.

Without a kilt pin I notice the outer apron edge will sometimes flip up in a stiff breeze such as when rounding a corner of a building and getting caught by a gust. But that gust needs to be in the magnitude of 30mph for the apron to flip up. Even a small kilt pin stops it.

In the Cargo and Casual Models I use buttons for the apron closure and they extend lower than the hip strap and that helps too.

I can't compare my fabrics to that of Amerikilt as I've only seen two of them, but those who own both report that my fabric is heavier and my construction puts more weight lower down on the kilt.

I hope this helps.