Material recommendations for metal strips on paging conveyors?

I'm upgrading a bag-feeding conveyor to include an in-line printer (pic below), and in order to keep the bags from shifting while under the printheads I added some tensioned metal strips like many paging conveyors seem to have. First, I tried making my strips out of aluminum, which helped but weren't springy enough. Next, I tried some 26 gauge galvanized sheet steel, which performed slightly better but was too flimsy for lengths over about 6 inches. I'd honestly prefer to just stear clear of galvanized coatings altogether if I can help it. I've searched and searched for what these metal strips are called, but my google-fu has been exhausted. The only direct mention of them I've seen is in [this video](https://www.youtube.com/watch?v=jbblAuKkRzo) where they're just called "metal strips." -.- I'm assuming they're made from Stainless steel, but is there a specific alloy/gauge that works best in this application? I don't have any intuition for Stainless so if you do, speculation is welcome! [What're thooose](https://preview.redd.it/vjnt4mc5g0fe1.jpg?width=2048&format=pjpg&auto=webp&s=8cf356684d83f05979868b54cc872b6e1437db70) [Attempt 1: Ducting Sheet Metal](https://preview.redd.it/h3jz5nc5g0fe1.jpg?width=1920&format=pjpg&auto=webp&s=81912eab13cc99ac8313448cff1b5cb7c207a913)