I am not able to judge the cost and weight of a set of curtains from a photograph, but they don't appear particularly cheap and flimsy to me. Therefore I'm not prepared to speculate about how they might behave. I'm also aware that there is disagreement about the weather that evening.
Look again at the curtain photos Gunit. See how cheaply they fall and how the light penetrates. Remember Matts statement where he could see light coming through them and the light was a mixture of sodium lighting colour yellow and the blue of the curtains IIRC. Cheap fabric; they didn't need sturdy fabric, cos they had shutters for excluding light and prying eyes. In actual fact they were merely a window dressing. Very thin fabric.
Additionally we all know that nets are very flimsy
Do not try and change the weather Gunit. That would be absolutely and totally dishonest.
The official weather reports have been posted on this forum several times. I observed years ago that some have been deleted and I wondered why?
I wonder if there are any actual bona fide weather reports, (without alteration) still standing on here, but I ain't wasting the time searching anymore