I think the easiest way is to make tiny stockpiles of desired materials near corresponding workshops. Dwarves just grab whatever is nearest, so make like a 1x3 stockpile of steel bars by the forge, steel moods guaranteed. Works for all materias and shops as far as I know.
Indeed, though it is a real pain to organize everything because then I have to do the same for every other industry or possible mood and then theres designing it so the hauling times arent eternal. As an architecture student, disorganized organic growth of a fortress and "making room as needed" makes me a very sad panda.
I seem to recall that forbidding materials makes no difference for an artifact. Neither does whether a stone is considered economic or marked as not for use on the Stone screen. Moody Dwarves use what moody Dwarves want to use.
Ive made lots of custom material artifacts by selective forbiding via stock screen
It may be then that forbidding from the Stocks screen and forbidding from the Stone screen work differently, or that it has changed since 40d.
I dont think Ive ever used the stone screen to forbid anything, the stocks screen has always sat right by me. And should a moody dwarf haul an undesired good into the workshop (say brown jaspers instead of that juicy black diamond you bought just for this ocasion) you can always forbid said item from the stocks screen and the moody dwarf will look for the next one available.
If I had known Urist McArmorer had sneaked a silver bar inside instead of all the steel bars laying around I would have instantly forbid all silver bars.
You know what probably hapened now that I think further on it? Some dwarf must have been hauling the silver bar just as I was forbidding all the items in the stocks screen and only afterwards he placed it in the coresponding stockpile. It happened before when I forbade every log except tower-caps, a woodcutter brought in an acacia log and the moody dwarf grabbed that instead. Lucky I laways follow the moody dwarf around and check his inventory.