Hulk could surpass Superman in seconds.
Matter of fact, if the fight starts at 12:00 in the day, by 12:01, he could be way beyond Superman.
His strength and increase rate is too much of a plot device for any definites to be said.
He's jumped to near infinite levels while not extremely pissed, but has been knocked out before he's reached those levels.
Superman vs Hulk is never a set match, cuz Hulk doesn't always require time to get pissed enough to do damage.
Just like sometimes Flash needs to accelerate to get to lightspeed, while others show him to have instant lightspeed. Hulk is the same way.
But damn if Marvel hasn't been neutering my boy lately......They need to give him some more hardcore feats.