I've been debating how to finish my basement ceiling, and came up with an idea that I haven't seen, so am looking for guidance.

String Art, coming to some kind of focal point at the chandelier. The ceiling in question has most of the joists in the area center covered by cold air return galvanized steel. My plan is to paint that black as the string art background, and then incorporate something like this pic.

The trick is going to be how to frame it up there. I'd like to be able to create the string art in a metal frame on the ground and then hang it all up on the ceiling in such a way so that it looks incorporated. I plan on drywalling around the edges of the ceiling a few feet out in order to hide the corners. The galvanized cold air return is roughly 5 feet by 9 feet. The room area is around 22' x 18'ish.

Its the details of getting it to work together that I'm not certain of. I'm also worried about whether the string will go slack over time and get droopy.