I do not know where Nathan's sources their mesh from but here is a link to what seems to be a very similar product.
It is 9.5 ounces per square yard.
Seattle fabrics also has its 8600 polyester dive mesh.
The website doesn't specify the fabric weight.
I'm also looking for a durable and easy to work with mesh fabric.
I contacted Quest Outfitters and I will soon be receiving a sample swatch of their #1204 POLYMESH- soft finish fabric. This mesh fabric has holes that are approx 1/8" x 1/8" in a somewhat diamond shaped. This fabric's weight is 7.5 oz per square yard.
I will post a picture of this fabric as soon as I get the swatch in the mail.