Shedd never complained about me sticking my camera hood against the glass. Neither have the National Aquarium in Baltimore or the Tennessee Aquarium in Chattanooga, which I thought was better than the others by far. My biggest problem at the Shedd was minimum focus distance. Ended up with much better photos with my old point & shoot than I did with my DSLR in many of the tanks, because it could go close to the glass and still get photos. The rubber hood is a great suggestion -- I need to get one of those. But you can also use a little dark cloth or something.
And you'll still have to retake a few photos because some dumbass takes an ipad photo with the flash on.
If you go to the dolphin show, don't bother adjusting your exposure for the bright sunlight coming in through the windows -- they block them off completely as the show is starting, leaving you in the dark futzing around trying to reset your camera.
There's a door near the otters (I think -- I have otter photos, then outdoor photos, then back to coral or something) that takes you out to a little outdoor seating area... great views of the city skyline from there.
The telephoto will only be useful for the dolphin show. Mostly stick with the wide end.
And this is one reason why I have amazon prime -- last minute orders of things for vacations.
The only really good photos I got out of my last trip to the Shedd were the jellyfish and the dolphin/whale show, and maybe the penguins. I don't know if the penguin photos were all that great, but they were fun to watch