I'd say it's not holding too closely to actual history, eh?
I've been in several of the "grand theaters" people like Houdini and Blackstone worked and believe me, they weren't all that grand. Most were quite dinky.
In Springfield, Ohio (USA) there is an abandoned theater that was, for many years, the booking house for the Vaudiville circuit. Anyhow, if you go backstage you will find a wall signed by all the acts that once played there including Houdini, Blackstone, the Marx Brothers, George Burns & Gracy, and many many others.
If I recall correctly, the theater seats about 300 e.g by today's standards, it's relatively small.
Few of the "Masters" of the so-called Golden Era ever performed for the massive audiences many of today's performers know on a regular basis. When you stop and conisder that Robert Houdin's entire circuit covers an area about the size of San Francisco and yet, he's seen as the "father" of modern magic, it's something that lends reason to pause and think a bit.
It will be interesting to see this film when it comes out and see just how close to historic fact they hold to.