Ok, so this is going to release between Zootopia and Illumination's Clifford...
Maybe this should release on May 20th? Would still give it a month before Finding Dory...
Big Hero 6 should certainly beat other original animated films lately OS like Wreck it Ralph and Lego Movie.
I think a good target would actually be around How to Train Your Dragon 2 OS number.
What I liked more about Big Hero 6, than say, the Lego Movie, was that this made me use all of my emotions throughout the film.
I was barely sad during the Lego Movie, that felt just like an ADD film to make us happy. This on the other hand, made me happy, excited, and sad, sometimes all at the same time.