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AEB-L. ATS34, cmp154 (basically the same as ats34) are all stainless steels that would work. I would use the RC hardness that Bruno recommended. Razors are not really that tough but need to be hard...

I would shoot for a 16 degrees total at the edge. Yes both sides need to be hollow. Once both of these criteria are met you can scale the blade to whatever width you want any where from .625 to 1 are...