Haha! Didn't realize I was setting you up so nicely.
After reading y'alls posts above, I am a little worried about the hole getting clogged with ash so I want to make it bigger and want to make sure its sealed off on the bottom. Since its only a single 1/4" wall I might drill a 1" hole where the 3/8" one is and then weld the bottom of the hole to ensure there's no place for water to leak down. Might have to do a little grinding to make sure the weld doesn't prevent the water from escaping downhill.
Also one more thing I could do is weld a little bit more and thread the hole to insert a 3/4" threaded rod. We'll see.