I make proofs at about the same size and I tend to see less noise when print than I do on the computer. I also, when sharpening, do selective sharpening. That being, I sharpen the whole image and then mask it all out. I then paint the sharpening effect back onto the subject or what ever else I want sharpened. I usually don't want to sharpen blurred out backgrounds or skies. I sometimes do light sharpening on interesting cloud formations. With an emphasis on "light sharpening".