Gathering & Crafting AF?

[Synfrag]

You can if you wished to, I know there's a level 50 crafting set weaver can make called Patricians that has some materia slots.

Whether doing it that way is better than getting each crafter's individual af, I haven't a clue but it's possible if you wanted to do that.

It is not. If you want the best you have to go with individual class specific sets for each craft. Other than that the options are Patricians set or a combination of that and a HQ Dodore Doublet. It will be extremely difficult to hit the required craftsmanship and control required to make the highest level recipes with a universal set and it will require forbidden melding.