I haven't gone that deep, but I've collected a motley assortment of materials for combination. None of them actually combine successfully, mind you, due to inadequate skill level. Can one acquire these skills, or do you need to select them during character creation? Knowing which way it goes would help with inventory management, to be sure. I guess the same question applies to the other skills. I'm tempted to just select all the proficiencies so I'm able to make full use of the dungeon's resources. I suppose I would lose out on other, cooler, abilities, though.