Metal blunt and bladed weapons to Filmore. Wooden weapons and bows to Whittacker. Staffs (and other caster-oriented weapons?) to Eleanor.
Take a copy of a weapon to the appropriate NPC. Exchange that weapon, along with some additional cost (maybe some coin, plus some/all of the crafting mats that would be required by the soon-to-be crafting blueprint?), to receive a crafting blueprint for that weapon.
This could go some way toward mitigating the “I don’t get tier 1 drops any more now that my world is tier 3” issue. Also it would be handy to be able to craft multiples of a specific item if you know your build favors that specific weapon, without resorting to mindless farming (which then in turn encourages savescumming or duping or other less-than-savory stuff).