I don't think you can technically call a stick saver die cast or triple-flanged...that's my thought anyway. I think it's closer to a quadruple flange considering the top is completely rolled over to the inside (with essentially two bends, the other two being at the base to accomodate the head collar), while a triple-flange is rolled out at the top.
I you want to stick with the look of a stick saver, you can get repros nowadays from catalog/internet stores like Explorers. Mapex even makes what they call Sonic Savers that are basically a stick saver.
I don't have the knowledge of chemistry and metals to say with any certainty, but I would think a die cast hoop would come closer to replicating the effect on tonal qualities that a COB stick saver would. That's only my opinion and I hope it helps.
I would just use the stick saver, though. If you bend it with your stick, you can massage it back out with a rubber mallet or a hammer and a folded towel.
There's my :2Cents:.