To quote somebody relevant, the only stupid question is the one you don’t ask. We’re all here to help each other. Don’t mind the odd bit of bickering. It’s how we all benefit, by thinking outside the box.
Those bags will probably work fine. Good score! Check out the link I gave you earlier. It explains how air pruning works. You’ll grow some pretty hefty plants in those bags.
Don’t need to go searching for a number Rob. Way too much much effort. Have you got one? How does it feel? Flimsy, or got some meat to it? Next time I’m in the area I’ll drop into the local PA and check one out myself, if they have them.