I think the chance for Sony to greenlight a fast tracked big budget sequel rests with foreign box office. Domestic box office is highly likely to be no less than $ 110 million and no more than $ 120 million. If foreign box office simply just about matches domestic that would lead to a worldwide gross of $ 220-240 million, which would be a mediocre rate of return (a couple of steps behind Daredevil, Constantine and LXG and a couple of steps ahead of Hulk) that would certainly turn a profit but not necessarily one big enough for Sony to greenlight a sequel, especially one with a bigger budget.
Still, there are a couple of other sequel options. Sony might opt to make a sequel at a lower budget level or they might decide against a sequel entirely and leave it to Marvel to self-finance another GR film at some point down the line.
For Sony to take the leap and make another big budget GR film with Nic Cage you'd pobably have to see the foreign gross be good enough to push the worldwide number up to the $ 270-280 million range. It would be unusual for a comic book film to make more in foreign than in domestic, but not unprecedented, and GR may have a shot at doing so since it's a supernatural actioner rather than a costumed superhero film.