For the record, Glover played Dr. Jason Woodrue in Batman and Robin (an Atom villain who would later become Floronic Man/Plant Master in the comics and join the Secret Society of Super-Villains).
As far as Shazam's estimated opening weekend box office is concerned...
Box office Mojo is comparing Shazam's opening to Ant-Man (2015). Ant-Man went on to a $180 million domestic and $519 worldwide overall.
https://www.boxofficemojo.com/news/?id=4501&p=.htm
Shazam is now at an estiamted $56.8 million domestic and $158.8 million worldwide. Mojo is giving an early forecast that Shazam might top out at $160 million domestic.
As much as I would want to see Shazam do a lot better than Ant-Man, in an earlier post I did mention that since Shazam's budget is about half of Aquaman's, if it can get to half Aquaman's total, it should be at about the same level of profitability.
By that metric, $575 million worldwide by the end of its run is the number to look out for to be considered an Aquaman-level success. So, it would seem that anything over $500 million worldwide would make Warners happy even if it's not Aquaman-level happy.
Going back to Ant-Man, it should also be noted that Shazam even has a lower budget than that movie. Ant-Man had a production cost of $130 million.
I hope that if Shazam does hit $500 million, then that will convince Warners to pipeline other moderately budgeted DC movies. Not every property can support a $200 million budget, and this way, we'll get more obscure-but-interesting properties into the cinemas.