Good question Jeff.
In my view, they each are options. It depends on what type of knife it will be, how big it is, what steel it is, etc.
I use primarily # 1 and 3. #2 is for very long knives or swords, although I am sure that it could be done to good effect on any knife.
The blade that I recently quenched with the hamon in the other thread, I full quenched, but covered the inside of the hamon area with clay before I quenched. So, I am saying that it depends on what the blade is for the effect I want or if I even want that effect.