Any advantage covering 2018 supply for winter?

I paid $5 per sheet for 25 that were 10-12' long. I think I grabbed 19 12 footers and 6 10 footers. I think I got. Good deal. There are places that are selling the old roofing for $2 per square foot to people who want old rustic barn parts. Those prices are crazy.

Here's one of my chipmunk condominiums. They are pretty far behind on the rent but I can't find a way to evict them yet. I haven't had a metal roofing sheet blow off yet. For reference, the sheets are doubled up and 26" wide with weight on the top. My wood is cut to 18-19" and the stack is 40" wide plus or minus an inch or two. I let the roofing overhang by a couple of inches. This is black birch, red oak and ash.

 

One thing that I found with the tin roofing is that in sustained higher winds, the edges and corners want to flap up and down a bit. As they do, they can move the top weights laterally just a little bit at a time which if it happens long enough, the weight could be too far from the edge to prevent a gust from ripping the sheet off the pile. I have countered this by using heavier weights and weights that are less likely to roll or slide. Granite cobblestones and cinder blocks are now my weapon of choice. The cobble stones alone were not heavy enough for isolated stacks (those not grouped together in parallel). But the addition helped significantly.