Questions regarding '52 through '80 Topps

[steve B]

For 72, they should be the same for each card on a sheet. Key word "should"

The screen is done when photographing the original art. each color is done at a different angle to help the halftones create a good color picture.

So the big negative used to make the plates - the mask- should be the same for all the plates.
With variations, like the Cubs lettering differences, it depends whether they did the correction by altering the mask, or reshooting corrected art. Things like a change in the checklist would have been new art, and each series might be different from the other series.
It's also possible if they had for example wax packs made in one plant and cellos in another that the different plants may have screened the colors at different angles. (Yes, that opens up the possibility that a true master set is slightly more than two full sets.)

Topps combined halftone and non halftone, making it a bit more complicated at times.

By the late 80's, it was a free for all. 88 score was screened differently for different printings. Along with three different die cuts to separate the cards.
I haven't investigated earlier Topps or other sets, but it's sort of on the list.