Even with some moderate skills in blacksmithing, nothing can be done with superheated or red hot heated stocks (yet). It's not good to work on those, and certainly not the best way to train blacksmithing, but if you happen to overheat them by mistake, quenching them would also make their quality drop, so it's not much difference if you hammer or quench them. I think there was once a bug though, that turned steelstock of any amounts into a handle, when being overheated and quenched twice, so i would still recommend hammering such stocks, although I'm not sure if that bug is still up to date.
However, the best way to get practice in blacksmithing is by hammering stocks and blades, because that way you also get practice in weapon making for each step on the way to a delta blade. Once you've reached the status of a delta blade, you can superheat or red hot heat the blade and then hammer it, which gives you back the respective amount of stocks you used for the blade, yet with a lowered quality. This is still the best method to train crafting skills though, and high quality steelstock isn't necessary to have until you are level 30-40 in weapon making anyway.
PS: Yeah, the books are a mess and give you a headache when reading them
