I fear that people are hyping up the estimated size far too much. The Drydock at Dalian is only roughly 366m long. There also needs to be a minimum separation distance between the ship itself and the ends of the drydock.
What that needs to be, I have no idea. What I do know is at least during the Fujian's construction, that distance was around 20m on both ends. Does that mean the 004 is capped at 326m long? No. But I just wanted to point this issue out to those convinced it may be a 340-350m long monster.
I think at this current point, expecting it to be a Ford ballpark sized ship is within reason (20m longer than Fujian is viable for instance), but beyond that is pushing it and somewhat unsubstantiated for now.
Tbh I'm not even sure why some people think it might be 120k tons or whatever, I assume it is just for the sake of chest beating.