Ok, now we know a bit more what we are talking about but optimal hardness is going to have to be determined by the intended usage of the blade. An HRC of 61-62 is a little high for most blades but some something that is going to be strictly a slicer, like a skinning blade, may do well with that hardness but that that would probably be a little too high for something that will get rougher use. Remember, edge retention is only one factor here, there is also the toughness of the blade to consider. A blade for rougher use may need more toughness than O1 can deliver at an HRC of 61-62 and you might need to temper 25-50 degrees higher to get a softer but tougher blade. If you want a blade with some flexability in it I would recommend something other than O1. Instrument testing can only take you so far. In the end you are going to have to design a blade for a certain job and then test it in use to see how it holds up whether it is slicing things like rope, skinning animals, preparing food, chopping wood, quartering large game, or whatever.
Doug Lester