I won't claim to be the world's greatest sewing machine operator, but I can stumble along. I owned a factory shelter that weighed 8 ounces, and then I got another factory shelter that weighed 8 ounces, so I put together some ideas from each one and sewed my own for 8 ounces. The advantage of making your own is that you can change the standard dimensions to make it longer, shorter, taller, or whatever. I went with one of the lighter weight fabrics, but it seems to work. I've slept under it only four nights so far, but it has been rained on and it still works.
Are you asking about thickness of grosgrain, or the width? I used some pretty common stuff, maybe 1/4" wide. I did not reinforce the tie-out points, but I sewed the grosgrain into the hem in each direction.
I also added some "storm flaps" that I can attach in a hurry to the rainy side.