Sorry for the late reply, I've been away from my computer for a while,
All I know is that you get a nice flex / resharpening frequency with a
56hrc blade and the 63hrc blade snapped when I tried putting a 9 inch
blade to about a 45 degree flex.

The 63hrc blade does make an exellent trout knife, it doesn't need to
flex like a fillet knife does,,, so if you can accurately temper (draw)
it back, yes the power hacksaw blade will work great.

If you are grinding it clamped to a board you most likely are getting
the blade hot enough to be drawing the hardness down a bit anyway,, but
you have to be real lucky to be able to do it that way consistantly
without burning the blade, although soaking the board with water might
help a bit as a heatsink.

I grind mine held in my bare hands with the blade supported with my
fingertips so when I start at 63 or 65rc I finish at the same hardness
because my fingers won't let me hold onto a blade much over 200degrees
F. (it's a very slow prossess)

When I read "full hard" in the first post I thought you meant to leave
it that hard so I may have miss-read your intent.

Happy grinding,
Bear

I'll catch back up with you in a week,, the ice just went out of the
lake my parents live by this past week,, I'm after some of those 2
pound crappies so I can test out my 10inch fillet knife.