I LOVE the Attic! I am having my post-wedding brunch at the Attic. Have you actually gotten to visit the space yet? I have and I don't think it would be big enough for 55-60 people AND a dance floor/DJ set-up. Plus, on the material I have for the Attic...it says that it accomodates up to 60 but adding in a dance floor, it reduces the amount of people it can fit. I would check with your coordinator (if you have one already) to be sure but I am guessing that it won't. I hope this helps! Good luck!