Can someone help me learn a little bit more about razor design ... I've seen a lot of discussions about blade gap, and about open vs closed comb razors. But I've seen little about the curvature of the blade as it sits in the head. Is this of no importance other than what angle you hold it at while shaving? In this thread it seems that the "flatter" blades is thought to be more aggressive, but of course there could be lots of reasons for that other than blade curvature. Nonetheless, I'd be interested in knowing if there is thought to be any general relationship between the blade being held relatively flat, vs curved, in terms of how "mild" or "aggressive" a razor is.