hey badbowtie...i tried both pvc and fiberglass sail boat batten, and both did exactly what you said, they bowed down and sideways. i am not sure how they are made but i instead spent the $150.00 for the center support arm. i have had no problems with it. i have a seasonal site and my awning stays out all the time as i have an add a room. i got it two years ago after a massive rain storm collapsed the awning and i wasnt going to have that happen again. 2 years later and many heavy rainstorms and wind, and still no problems. totally recommend it.