Clearly different strokes for different folks on the subject of O1. What's really amazing is that we apparently all get good results no matter what process we use. That may be more of a testament to O1 than to our heat treating
FWIW, I just follow what Latrobe says to the best of my ability. There are many different data sheets for O1 online and they aren't identical but they don't differ greatly as far as I have seen. Latrobe says heat the steel slowly, no more than 400 F per hour. Well, I start with a cold oven and it heats slowly but faster than 400 degrees per hour. Latrobe says nothing about pre-heating the oven. Then they do the 1200 cycle and then up to 1475, the process most of us seem to follow. I think the details of most 'official' O1 data sheets strongly apply to complex parts but are much less critical for simple blades.
My oven is flooded with argon to limit the scaling. Grinding post HT eliminates any scaling that does form. I grind bare handed on fresh ceramic belts with a bucket of water to dip in when the blade warms up. With a fresh belt I find grinding a hardened profile to be only marginally more difficult than unhardened steel although it takes a little more time. I do this routinely with 3/16" and thinner blades but would do some of the grinding before HT on anything thicker.
All of this is not to change anyone's mind about how they do their O1 but I did want to provide the details of my process and why I do it that way ...