Here are more background comparisons:
Slave 1 load:
Slave 1 leave:
These backgrounds do not match at all, and the clouds behind the close up of Fett match the load screen and not the leave one.
Falcon arrive:
Falcon leave:
The shot of Han walking towards Lando and the shot of Lando and Co running towards the Falcon match almost perfectly. Everyone walking straight towards camera is a really good match to the Falcon blasting off. It all looks good, except that none of the clouds matching the more CGI shots.
So my vote is to change Slave 1's background in all the shots, because the Falcon one's match fairly well.
Ramp arrive:
Ramp leave:
The ramp towards the city has the fancy CGI background that kind of matches the original matte, but as they leave its back to the matte. Maybe we could recolor the CGI to replace the matte as they're leaving.