Stainless screws

I've read here of folks replacing their exterior screws with stainless ones. I'm about to start re-skinning my 1981 12 1/2' MC and will need to replace all the screws. When I search, I see zinc-plated, and something called "Stainless 410", which states, "A stainless alloy that is harder than 18-8 stainless steel, but not as resistant to corrosion." After pulling out so many little blobs of rusty metal that used to be screws, I don't like the sound of that. Is this what I'm supposed to use? Can anyone help me out with a source?

Thanks!