(1) I usually cruise on Deck 2 with a Porthole. I have pictures that show just how close to the walls the Magic / Wonder are during transit. It's Amazing!!
(2) The mules only kept the ships centered and straight (most of the time). Actually, the ships have to drive themselves into the locks, and it's hard work! Simple physics - the ship displaces so much water - when its in the open ocean the water the ship moves into gets "easily" pushed aside (since the ocean is HUGE). When moving into / through the the locks, there is only a 110 feet wide by 2,000 feet long (two 1000 foot sections open at the same level and time) box to push the water aside / around in. When the ships are moving up/down in the locks, look at their smoke stacks - "nothing" is being expelled. When the ship starts to move into the next lock, the smoke stacks are billowing out a lot of smoke. My source of this information is through observation after it was explained to me by
Captain Puckett who was a canal pilot for many, many years.
as a side note - when the Wonder was in San Diego last week we could see the pretty big dent that the cherry picker left in the side of our ship!