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It should be ok tempering while ground thin. I would temper for an hour each time. It is not getting hot enough to burn carbon out, honing should take off where you left it, no need to remove extra...

I would go up in intervals of 25 degrees until the steel acts the way you want it to. If you did 400 then try 425 and so on till it where you want it. You have to experiment to find out a process...