I saw that about the zinc too.
Cut the bottom out of my drum since the weber lid fit easier. I am going to try and use the 2" bung on the bottom for my intake. I saw that most others end up only using 1 intake with a valve and the others capped off on the sides. Would it be any different using an intake in the bottom, not centered. Thought I'd come in through the bottom and put a 90 elbow on it so ash wouldn't get in it.