Okay so I haven't really been able to find clear answers to some of my questions about making the Staff of Herding:
-Do you have to find the items on the difficulty you want to unlock? I found the mushroom a long time ago on Normal, will that work if I want to go to Hell Whimsyshire?
From what I understand, you can find all the items on normal and then you just "upgrade" the staff with gold and plans. Is that how it works?