Oh, well done you for your research! This is very very helpful.
Since they say this:
we should definitely follow those instructions to the letter. That means, DON'T use the Image Size feature. Only use the Crop Tool.
Can you choose your Crop Tool, then show me a screenshot?
If you think they're behaving differently, it's probably because you're not used to the noise of your new camera, I figure.
Have you opened an old raw file to check?
Because your lab don't change the way they print just because you got a new screen! Can you imagine having to call the lab to tell them to print differently because you have a new screen? Can you imagine EVERY photographer calling the lab to tell them to print differently? Of course that's impossible.
No, no tutorial necessary. The noise layer you always add to a gradient is a form of texture. Any other texture, you add the same way. Place it, clip it, then play with its blend mode.