Quick note to anyone looking for storage place just outside of the city. I just moved my 720s to this place: https://www.alphagaragechicago.com/ I love it. The owner is a real car guy. The place is close to downtown, has great security, has a really cool vibe, the potential for some social elements with other car people (it's already filled with some AMAZING cars), and is just an all around fun place to be a part of. They also have VERY amazing and experienced detailers right there who can do it all. No affiliation at all, just a happy customer.
I forget the exact amount, but - it was like $5k for a whole year. They've just been so super helpful - especially for me as I don't live in Chicago full time.