Alright i'm just adding on to this post as it's still general game knowledge but something isn't adding up. I've got the usual R8 gear from the recast guide that is already available yet when I go to upgrade it at the forge the armour/weapon itself doesn't show up. I have it in my inventory but for example the "Twilight Dark song" daggers require the Ocean Supreme Daggers yet it still shows at 0/1 despite it being in my inventory. Do I need to upgrade them somewhere else first and come back?
Ignore this, i'm dumb. figured it out that you actually have to drag it into the slot.